Anime movies based on popular TV shows are far from uncommon. Just take a look at all the awesome movies spawned from One Piece, My Hero Academia, and Dragon Ball Z. However, there are a lot of fantastic anime movies that would work as TV shows; allowing them to tell their stories unabridged.
Movies like Akira - which wowed audiences worldwide when originally released - had to sacrifice so much of its source material, just to fit within the limited runtime of the silver screen. Even original anime movies like Promare could use more time to play around in the wonderful world they just created. There's also the matter of fan-favorite manga series that surprisingly only received an Original Video Animation episode or two, instead of getting the traditional TV season they deserved, such as the cult classic Battle Angel Alita. These series and more deserve more time to shine on the smaller, but still prestigious, TV screen.
Black Fox is an original anime movie about a 16-year-old girl and her superheroic alter ego. Rikka Isurugi was a somewhat ordinary girl who was following in the footsteps of her scientific father and ninjitsu grandfather, until a paramilitary group raided Rikka's home and murdered her family over her father's research in drone technology. Months after the massacre, Rikka is now a private detective who dons her grandfather's fox mask at night to hunt the killers behind the attack. There's a Marvel superhero aura over Black Fox; opening itself up for more stories about its ninja-esque heroine and its equally entertaining cast of characters.
Before it was a live-action Hollywood movie, Battle Angle Alita was a two-episode OVA that was released in 1993. The story follows a female cyborg named Gally living in a dangerous post-apocalyptic world known as the Scrapyard. After being rebuilt by a Cyberphysician named Doc Ido, Gally searches for her memories as a bounty hunter. Despite being a critically-acclaimed manga, Battle Angel Alita only had a short-lived run in animation. While two of its manga volumes were adapted into an anime, there were seven volumes of Battle Angel Alita still left to tell.
From the people that brought you Tengen Toppa Gurren Lagann and Kill la Kill comes Promare, a 2019 anime movie about a rag-tag team of firefighters going up against a terrorist group of mutated arsonists. The post-apocalyptic city of Promepolis is protected by a team of mecha firefighters known as the Burning Rescue. When Galo Thymos, an energetic rookie of Burning Rescue, goes up against Lio Fotia, the alleged terrorist leader of the Mad Burnish, their chance encounter will lead them to uncover the dark truth of Promepolis. As entertaining as Promare was, the 111-minute movie barely scratched the surface of all the cool ideas and characters within it, such as the minimal screen time given to the Burning Rescue team. An anime TV series of Promare would provide a more fully-fleshed out world and also strengthen the relationship between Galo and Lio.
Kase-san and Morning Glories is a 58-minute OVA based on the yuri manga series of the same name. The romantic slice-of-life movie revolves around the unlikely relationship between Yui Yamada, a timid high school girl, and Kase Tomoka, a popular and athletic tomboy. Kase-san and Morning Glories does a beautiful job of animating the early chapters of Kase-san, but there's so much more that's left on the table. The manga series not only covers Yui and Kase-san's relationship through high school, but has now expanded to their lives as college freshmen.