In a few books, it's been implied Ace was bisexual, and confirmed in the case of Mike Yates (that is, confirmed as long as you consider the books canon). The main cast of Torchwood is at the very least bi-curious (Jack Harkness is pansexual, Owen Harper and Toshiko sato are bisexual, Ianto Jones seems to be gay only for Jack, and Gwen Cooper has shown some curious tendencies). Oswin Oswald said she "fancied" a girl named Nina, but referred to it as a "Phase". Izzy Sinclair, a companion from the 8th Doctor comics, was the first gay character of the series.
- The Virgin New Adventures novel Damaged Goods (written by none other than Russell T Davies) established the companion Chris Cwej as being either gay or bi (this occurred around the same time Izzy was "outed"). Mike Yates was established as being gay in a couple of the New Adventures novels as well (however Ace is firmly heterosexual, having several male "friends"). Another comic strip companion, Fey Truscott-Sade, was depicted as bisexual (and shares a snog with Izzy in Izzy's "coming out" story). Capt. John Hart of Torchwood also carried a torch (sorry...) for Harkness.
- In addition to all these, gay one-off characters have also appeared in numerous episodes, including "Midnight" and "A Good Man Goes to War".