The only ones that are definately missing AFAIK are the appearances for "Seven Seas of Rhye". From an official viewpoint they don't exist as the TOTP editions were wiped... BUT there are copies circulating on bootlegs (unofficially) in bad quality from before the junking occurred.
I've heard there were also appearances for "Now I'm Here" but don't know if that's true. If it is, their status is most likely the same story as "Seven Seas of Rhye".
Also, the dance group Pans People performed to Queen tracks for TOTP but I don't know if these still exist.
All the others have been released. "Killer Queen" and "Good Old Fashioned Lover Boy" on Greatest Video Hits 1 and "Las Palabras De Amor" (used as the official promo video) on Greatest Video Hits 2.
Yeah forgot about that Roger Taylor performance. I've seen that on TOTP2 in the past. Brian was also on TOTP for "Ressurection". Not sure about the other solo stuff though? Anyone have a complete list?
1974 - Seven Seas Of Rhye (2(+?) appearances) (mimed - one appearance has an alternate audio mix, with echos on Freddie's voice)
1974 - Killer Queen (two versions - one on BBC's TOPT, and one on Avro's TopPop) (mimed)
1975 - Now I'm Here (reported) (mimed?)
1977 - Good Old-Fashioned Loverboy (mimed - alternate audio version)
1982 - Las Palabras De Amor (The Words Of Love) (mimed)
2000 - We Will Rock You (with 5ive) (mostly mimed, with Queen playing along to the CD track)
1981 - Future Management (Roger Taylor)
1991 - The Stonk (Hale and Pace feat. Brian May) (live?)
1993 - Resurrection (Brian May w/ Cozy Powell) (mimed?)
1996 - Reaching Out (Rock Therapy feat. Paul Rodgers and Brian May) (I think it's live...I'm not sure)
And there is a 1980's TOTP video of AOBTD with "Leggs Co." (correct name?) dancing to the song(!)
I think there is one too for Under Pressure with the same dancers, cos I saw a video clip on the BBC TOTP website that DEFINITELY wasn't the one on GVH1/GF/etc.! (the normal version)
Also, this might be stretching it a bit, but there was a Raven Maize appearance on TOPT with the song "The Real Life" which sampled BohRap, and the TOTP video even incorporated bits from the original BohRap video(!) on the video portion.
Can't remember what year this was, but it was within the last four years if I am not mistaken.