Supernatural Anime
Kono Subarashii Sekai ni Shukufuku wo! 2 OVA

Unaired episode bundled with a limited-edition of the light novel's twelfth volume.
One Punch Man: Road to Hero

While Saitama is training to become a hero, he needs one more thing before he can become a real hero. The origins of his hero suit is revealed.
Strike the Blood II

The second season of Strike the Blood which adapts three arcs from the 9th, 11th, and 12th light novel volumes.
[Source: MyAnimeList]
Devilman: Crybaby

Our protagonist Akira Fudo hears from his best friend Ryou Asuka that the demons will revive and reclaim the world from humans. As humans have no chance against the demons' power, Ryou suggests combining with a demon. Akira becomes Devilman, a being with the power of a demon and the heart of a human.
[Source: Anime News Network]
Highschool of the Dead: Drifters of the Dead

An OVA of Highschool of the Dead bundled with the 7th manga volume.
Komuro and the gang stumble upon a deserted tropical island that looks to be free of zombies. They make use of this wonderful opportunity and dress up in skimpy swimsuits and have lots and lots of fanservice fun.
Hallucinogenic substances are involved.
[Source: MAL]
Tokyo Ghoul: Jack

In Tokyo Ghoul: Jack, an incident involving a human-devouring Ghoul occurs in Tokyo's 13th Ward. To seek the truth behind what happened to his friend, the rebellious high school boy Taishi Fura pursues the Ghoul named Lantern with the young ace investigator Kishō Arima. The story follows how the ace investigator Arima and the talented 7th Ward investigator Taishi Fura first met.
[Source: Anime News Network]
Tokyo Ghoul: Pinto

OVA adapting the third story in the Tokyo Ghoul: Hibi novel when Shuu Tsukiyama and Chie Hori met.
[Source: Anime News Network]
Trinity Seven OVA

Arata is set to be expelled! The only way to save himself is to be taught more about the magic archives from the Trinity Seven themselves.
[Source: MyAnimeList]
Mirai Nikki Redial

The Second is dead and the Gasai Yuno in the third world finally gets to live a happy life with her loving parents and friends from school. But there is still an empty place in her heart — it seems she has forgotten a person really close to her but simply cannot regain her memories...
[Source: Anime News Network]
Yuragi-sou no Yuuna-san OVA

OVAs bundled with limited editions of the manga's 11th, 12th and 13th volumes.
The first OVA adapts the manga's 12th chapter.
Mob Psycho 100: Daiikkai Rei toka Soudansho Ian Ryokou - Kokoro Mitasu Iyashi no Tabi

Mob, Reigen, Dimple, and the newest member of the Spirits and Such Consultation Office staff, Serizawa, take a trip up to a secluded hot spring called Ibogami Hot Springs in Zebra Prefecture. Reigen happened to get a request from the matron there to discover the truth behind the strange rumors going around there and save the inn. Ritsu and Teru also join in on this trip and the six of them head out on this super relaxing trip to the hot spring. But on their way there, Reigen and Serizawa start nodding off on the train and somehow get sucked into an eerie parallel world...
[Source: Funimation]
Boku no Hero Academia: Ikinokore! Kesshi no Survival Kunren

In this brand-new adventure, some Class 1-A students are sent to hone their survival skills at a training course. Having yet to receive their provisional licenses, they’re eager to cut loose and have a little fun.
They quickly discover that the danger they face is no simulation! It’s going to take their combined training, teamwork, and quick thinking if they’re going to pass this assignment!
[Source: Funimation]
Angel Beats! Specials

Unaired episodes of Angel Beats! included in the seventh volume of the Blu-ray and DVD, and another included in the Blu-ray Box.
B: The Beginning

The story is set in the future where scientists have tried to create the "perfect human" in hopes of keeping peace in the universe. After nearly achieving their goal through several children, the scientists send their "new humans" for further training where they are kidnapped by an evil organization set on using their powers to implement their own concept of a new world order.
[Source: Netflix]
Strike the Blood IV

The fourth primogenitor is the most powerful vampire once thought to exist only in the world of legends. Yet when it appears in Japan, the government for some reason chooses an apprentice “sward shaman“, Yukina Himeragi, to observe and obliterate it. Bewildered by the disproportionate task and its specific details, Yukina arrives at the Demon District of Itogami-jima to watch Akatsuki Kojo, and a student at a private high school on Itogami-jima.
[Source: Hakuhodo DY Music & Pictures]
Strike the Blood: Valkyria no Oukoku-hen

Kojou and Yukina are on their way to school as usual when they find La Folia being chased by someone. Yukina crosses blades with the enormous man who's pursuing her, but before the fight can escalate further, La Folia makes a shocking comment: "Father, this is the Fourth Progenitor, Akatsuki Kojou... my first!" La Folia's father, Lucas, had told her to decide who she wished to marry, so she declares that Kojou is her choice. Lucas refuses to accept this, but then La Folia's mother, Polifonia, invites Kojou and Yukina to a party so they can all talk in more detail. When they arrive at the party, they discover that Asagi, Yaze, Nagisa, and Sayaka have been invited as well, due to their connections with Kojou. What sort of heated battle is about to break out between the many girls in Kojou's life?!
[Source: Crunchyroll]
Hellsing Ultimate

Hellsing, a secret organization of the British government, have long been battling supernatural threats to keep the people safe from the creatures of the night. The current leader, Integra Wingates Hellsing controls her own personal army to eliminate the undead beings, but even her highly trained soldiers pale in comparison to her most trusted vampire exterminator, a man by the name of Alucard, who is actually a powerful vampire himself. Along with Integra's mysterious butler and Alucard's new vampire minion, Seras Victoria, The Hellsing Organization must face not only regular ghouls and vampires, but a rivalling secret organization from the Vatican, and Millennium, an enigmatic group of madmen spawned by a certain war over 50 years ago...
A bloody battle between monsters is about to begin, the dead are dancing, and all hell is singing...
[Source: Crunchyroll]
Mob Psycho 100 Reigen: Shirarezaru Kiseki Reinouryokusha

A summary episode of Mob Psycho 100 which features commentary from Reigen Arataka.
[Source: MyAnimeList]
Koyomimonogatari

Koyomimonogatari includes twelve short stories about Koyomi from that destined Spring Break to the end of university exams.
[Source: Bakemonogatari wiki]
Mondaiji-tachi ga Isekai kara Kuru Sou Desu yo?: Onsen Manyuuki

Izayoi, Asuka, and You have been invited to participate in a Gift-Game at a hot spring village to help the small community there find a new water source.
OVA bundled with the eighth volume of the light novel.
Musaigen no Phantom World Special

Unaired episode bundled with Blu-ray/DVD volume 7 of the TV anime.
Ansatsu Kyoushitsu

The story of the original manga begins after 70% of the moon was suddenly vaporized in an explosion. The super lifeform responsible for this catastrophe is a strange tentacled creature that can slink around at supersonic Mach 20 speeds. It has a 10 billion yen (US$100 million) price on its head, but for some reason, this creature ends up teaching a middle school class at the beginning of the school year. The students have until graduation to assassinate the teacher, or it will destroy Earth as well.
The event anime special will adapt the original manga's popular segment about the field trip to ancient Kyoto.
[Source: Anime News Network]
Fate/Stay Night: Unlimited Blade Works: Sunny Day

The official website for the Fate/stay night: Unlimited Blade Works anime announced on Monday that the second Blu-ray box set for the series will include a 10-minute short anime. The short will adapt "sunny day," an alternate "good" ending to the "Unlimited Blade Works" route from the original Fate/stay night game.
[Source: Anime News Network]
Owari no Seraph: Kyuuketsuki Shahal

The episode features an original story with original characters, and features a special mission that takes place before the decisive battle in Nagoya. The anime stars a mysterious vampire named Shahal and a human girl named Rikowhom he kidnaps. Shahal's true goal is unknown, and while he's kidnapped Riko, he refuses to drink her blood. Suddenly, he receives a visit from the vampire nobles Ferid and Crowley. Meanwhile, Guren tasks Shinoa's squad with rescuing Riko and returning her to her family.
[Source: Anime News Network]
Kyoukai no Kanata: Shinonome

Bundled with BD/DVD 7.
Episode 0 takes place two years prior to the TV series when the Nase siblings meet Akito for the first time in a mission for Hiroomi.
Mitsuki follows her brother on this mission and their goal is to subjugate Akito.
[Source: MyAnimeList News]
Gabriel DropOut Specials

Specials included with the first and third Blu-ray and DVD volumes of the TV series.
Kore wa Zombie Desu ka? of the Dead: Hai, Minotake ni Attemasu

An unaired OVA episode of Kore wa Zombie Desu ka? of the Dead. It is the 11th episode and was bundled with the sixth volume of the manga.
[Source: MyAnimeList]
Mugen no Juunin: Immortal

Manji is an immortal swordsman, who has been cursed with eternal life. He has grown tired of living with all the death he has created. He has no skills other than those of killing, thus he forms a plan to regain his mortality: he shall kill one hundred evil men for each good one he has killed. The old witch who afflicted Manji with immortality agrees to Manji’s proposition and Manji is set on his path to kill one thousand evil men. On his journey he meets a young girl, Rin, who has her own vengeance to seek against the sword school whose members slaughtered Rin’s family. Rin and Manji journey together, each hoping to find some kind of peace. In their way are many varied enemies. Rin and Manji are almost constantly under attack and must learn to live their lives, avoiding being consumed by revenge.
[Source: Anime News Network]
Fate/Grand Order: Zettai Majuu Sensen Babylonia Episode 0 - Initium Iter

2017 AD. The last era in which Magecraft still existed. Society was created by human hands, but Mages grasped the truth of the world. Magecraft is comprised of techniques from past humans that cannot be explained by science, while science encompasses the techniques of future humans that Magecraft cannot achieve.
[Source: AnimeLab]
Kuroshitsuji: Book of Murder

At the Queen's behest, young master Ciel Phantomhive hosts a lavish banquet to be attended by the crème-de-la-crème of London's elite. What begins as a fabulous affair quickly takes a dark turn when guests begin turning up dead! Should Sebastian and Ciel wish to once more see the light of day, they must join forces with their guests, including the legendary author Sir Arthur Conan Doyle, to unravel the mystery—and apprehend the murderer before it's too late!
[Source: FUNimation]
Kami nomi zo Shiru Sekai: Tenri-hen

It is summer break and Keima intends to spend all his time on video games. An old acquaintance, the timid girl Tenri, comes back into the neighborhood - and apparently has a lost soul inside her. It is up to Keima and Elysia to unravel the secrets of her heart.
[Source: Anime News Network]
Mirai Nikki OVA

A short OVA that was bundled with the limited edition of the eleventh volume of the manga.
Ao no Exorcist: Kuro no Iede

Feeling slighted by Rin, Kuro goes on the hunt for a new master, but can he find anyone who can truly replace Rin?
Sankarea OVA

Two OVA episodes are bundled as DVDs with each of volumes 6 and 7 of the manga.
The first OVA is a prequel story written by the manga's author. Before the beginning of the main story, Rea and Chihiro have already met at a certain place: an outdoor hot-spring bath.
The second OVA takes place after the series (effectively episode 14). The Furuya family finds a mysterious young girl hiding under the household temple.
Yuragi-sou no Yuuna-san OVA (2020)

- Studio TBA
Two OVA episodes bundled with the manga's 24th (final) volume.
Episode 1: "Noroware no Kogarashi" (Cursed Kogarashi, adapting chapter 99) Episode 2: "Giri Giri!? Onsen Happening" (In the Nick of Time!? Hot Spring Incident, adapting chapter 141)
[Source: Anime News Network]
Blood Lad: Wagahai wa Neko de wa Nai

As Staz and Fuyumi are in their journey, Fuyumi has to consume Staz's blood once again to avoid disappearing and starts becoming addict to it. Meanwhile, a vampire hunter group targets Staz. While the vampire initially fights against them equally, he is weakened by a weapon made of silver and Fuyumi is kidnapped. Regardless of his weakened state, Staz heads to their headquarters where they attempt to kill him. Staz consumes their magic, leaving the leader to give up and let Staz and Fuyumi use his blimp.
[Source: Wikipedia]
Kubikiri Cycle: Aoiro Savant to Zaregototsukai

It's the vacation of a lifetime, a trip to a remote island filled with geniuses–and murder.
On Wet Crow's Feather Island, a tiny speck in the Sea of Japan, lives Akagami Iria, the exiled daughter of a powerful family. Born into great wealth, she was a princess of the highest pedigree–until she was cut off by the leader of the Akagami Foundation. For the last five years, she's lived on Feather Island with her maids. But she hasn't been alone. She has invited the best minds Japan has to offer to come and stay with her.
[Source: Del Rey]
Kamisama Hajimemashita: Kako-hen

OAD adapting the "past arc," which spans from mid-volume 14 to volume 17 in the manga.
[Source: Anime News Network]
Ansatsu Kyoushitsu (TV): Deai no Jikan

- Studio TBA
Episode 0 of the Ansatsu Kyoushitsu TV series screened at the Jump Festa 2014 events.
[Source: MAL]
Death Note: Rewrite

Genshisuru Kami (Visions of a God) A two hour episode of Death Note, mainly a compilation of the confrontations between Light and L, re-edited from Ryuk's perspective with new dialogue and soundtrack along with additional animation that could not be included in the original series. An Unnamed Shinigami comes to Ryuk to question him about his new story in the human world.
L o Tsugu Mono (L's Successors) This story continues where the previous left off, continuing the story of Light. As the previous special told Light and L's battles, this story does the same with the conflicts between Light, Mello, and Near.
[Source: Wikipedia]
Ajin OVA

New episodes bundled with the limited edition eighth, ninth and tenth manga volumes.