Cast Full of Gay

Anime & Manga

 * Strawberry Panic! has no men in sight anywhere, and almost every character is either in or pursuing a romantic relationship with another girl.
 * Yuru-Yuri has a main cast of eight girls, but one of the whom have romantic connections to at least one of the others.
 * Sakura Trick has an all-female cast, and, well, Haruka and Yuu are a couple, as are Shizuku and Kotone. Yuzu and Kaede aren't, but they are a pair of close friends with no noticeable interests in guys that willingly hang out with a group of lesbians, so make of that what you will. The only other major character, Mitsuki, has a crush on Haruka.

Video Games

 * Artificial Academy games by Illusion. It is the players choice of who (and what) they want in their game and to play as anyone in the class that they have created. You can essentially have a class full of girls only or boys only, as long as the 'homo' or 'bi' option for the character is set in the maker.
 * Although, when initiating 'H scenes' with two guys the game instead fades to black. But with Yuri scenes it's completely normal, albeit without many of the options hetro pairings have. Some understandable, some less so. Without modding the game there isn't any other way to "uncensor" the Yaoi scenes.
 * The Sims games allow you to create a situation like this, either in a single house/family or in a entire neighborhood, but all sims have flexible sexualities.

Visual Novels

 * Sono Hanabira Ni Kuchizuke Wo is a cast full of lesbian with parents and some expanded material characters being the only characters that show any heterosexual feelings.

Web Animation

 * In Hazbin Hotel, the majority of the cast running the titular hotel aren't straight. Charlie, the main character and Princess of Hell, is bisexual. Her girlfriend Vaggie is a lesbian. Angel Dust is a gay Drag Queen. Husk, the hotel's bartender is pansexual. Alastor, their Obviously Evil main investor, is asexual. The latter was confirmed in a tweet by the show's creator on National Coming Out Day.
 * Its sister series Helluva Boss downplays it but is still present, with three of the main cast members being confirmed as LGBT. Stolas being a Depraved Bisexual prince of hell, Blitzo confirmed in his instagram post as pan, and Moxxie was revealed to be bisexual in a tweet by Viv on Bi-Visibililty Day. Episode 5 also introduced Sallie May, Millie's transgender sister, as confirmed by a tweet from the voice actor.

Western Animation

 * Craig of the Creek has plenty of LGBT characters: Witches of the Creek, Tabitha and Courtney, J.P.'s sister, Laura and her girlfriend Kat and Craig's cousin, Jasmine, are lesbians, Angel is non-ginary, Merkid is agender and Pullstring, of the Plush Kids, is transgender. And there's plenty of Ambiguously Gay characters (such as Kelsey, Stacks, Junk Lord and the Honeysuckle Rangers).
 * OK K.O.! Let's Be Heroes has a very diverse cast of LGBT characters: Enid and Venomous are bisexual, Red Action is a lesbian, Boxman is pansexual, the Hue Troops are all LGBT+, Gregg is non-binary, Nick and Joff are a gay couple, Rad and Raymond are both queers, and there are a number of Ambiguously Gay or Ambiguously Bi characters (such as Elodie, RMS, Brandon, Pastel, and Koala Princess.)
 * The Owl House downplays this somewhat as most characters have no romantic relationships or crushes mentioned, but those who do are overwhelming queer - Luz is bisexual and her girfriend Amity is a lesbian, Eda is bisexual as shown by a flag on the side of her old lunchbox, and her ex Raine is nonbinary. Willow also Has Two Daddies and Edric is mentioned as having a date with someone referred to with they/them pronouns. When Dana was asked if anyone was straight on the Boiling Isles, her answers was "only Amity's parents".
 * Q-Force: Not all spies (minus Rick Buck) are straight.
 * Steven Universe: As Gems are a One-Gender Race, most of their romantic relationship are homosexual (even none of them technically have sexes). There's a significant focus on the loves between Ruby and Sapphire, as well as Pearl and Rose (the latter of whom also loved Greg, Steven's father), plus less explicit romantic tension between several others. Most of the human cast are heterosexual or their orientation is unspecified, but it's eventually shown Sadie is pansexual. Word of Saint Paul also outed Peridot as ace/aro.