Ongina- (Season 1) A fierce, fan-favorite queen who would draw attention to the series.
Morgan McMicheals- (Season 2) A requested and speculated queen to return to the show, who also canceled her gig for the Montreal Pride for August 17. And there's receipts!
Shangela- (Season 2, Season 3) Though she did re-appear on the show, and I said that there hasn't been any known queens that re-appeared come back, she did cancel her tour right before the filming of All Stars: 3 starts.
Milk- (Season 6) Her last known gig appeared to be on July 16th. She has free time for filming. She's also heavily requested to return.
BenDeLaCreme: (Season 6) A very requested queen to return who has rumors going around about her canceling gigs, with receipts.
Courtney Act- (Season 6) A talented queen who World of Wonder might want for "good TV" on the season. She was a runner-up on Season 5.
Laganja Estranga- (Season 6) A drama machine. Believe me, they look for this in casting.
Trixie Mattel- (Season 7) Another talented, runner-up. Also a fan-favorite.
Kennedy Davenport (Season 7)- Talented, would be an interesting mix with Chi Chi Devayne.
Chi Chi Devayne (Season 8)- Funny, fan-favorite top 4 queen, and her gig was moved to August 25 due to problems with scheduling. This gives her open time to film All Stars: 3, and it ends around this time.
Thorgy Thor (Season 8)- A nice, but shady queen. Her gigs were canceled around the time All Stars: 3 will start to film.
Aja (Season 9)- A very liked queen who canceled her tour from July 21 - July 29 in Australia. This is when All Stars: 3 will start to film.