A few have already been mentioned, but still:
Faith - Her crush on Buffy was so obvious it hurt lol.
Lenny and Carl in The Simpsons - They've kind of joked about it a few times, but I don't think they've ever said it.
The daughter in American Dad who's name is escaping me right now - IIRC it's been implied she's bi at least.
The title characters in Scott and Bailey, although Rachel more than Janet - what is it with police dramas featuring two women always being super lesbian seeming? See also Rizzoli and Isles, and Cagney and Lacey as has already been mentioned.
Sgt. Hathaway from Lewis - He's certainly curious, based on a couple of episodes.
Velma from Scooby Doo - Should go without saying i think. I get the feeling that the reason she was paired with Shaggy was to shut people up about it lol.
Fred from Scooby Doo - Daphne's a beard.
Pretty much anyone in Torchwood - IIRC it's been claimed that everyone is bisexual. I think only Gwen hasn't had an on screen same sex romance.
Amy Pond from Dr Who - probably bi anyway, flirts with a clone of herself at one point.
Ace from Dr Who - was written as a lesbian by at least one of the writers.
Luke from Sarah Jane Adventures - Apparently had the series not had to finish because Elizabeth Sladen died it was intended for him to come out as gay. IIRC Sarah Jane was implied to be bi as well.
Ashley Spinelli from Recess - you just know she's growing up to be an Ellen Page type lesbian.
Margery Tryell from Game of Thrones is implied to be bi.
And not on TV: I always assumed that Sunny Smiles and Trudy from the game Fallout: New Vegas were intended to be a couple (The run a bar together and share a house, and don't have any other love interests). What's odd though is that there are some other lesbians / bi women in the game (Veronica, Betsy, etc).
Lara Croft from the 2013 Tomb Raider reboot - basically confirmed by the writer.
