Here are some possible Thomas trades (other minor pieces and lesser draft picks included as necessary)
LAL - Thomas for Russell, Black
PHI - Thomas for both lottery picks (its own and LAL's - so say 4 and 6)
DEN - Thomas for Harris, Mudiay, Hernangomez
MIL - Thomas for Parker
MIN - Thomas for Lavine
ATL - Thomas for Schroder, 1st
ORL - Thomas for Gordon, and Payton or Hezonja
If NO keeps its pick (i.e. top 3) Thomas for the pick
If DAL ends up in top 3 - Thomas for the pick
All of those trades make sense if Boston moves Thomas and looks to rebuild. They aren't equal value for Thomas, but I don't feel they are terrible value either when you consider Thomas will be an expiring contract looking for a huge contract.
I don't think a single one of those teams agree to one of those deals, except maybe Atlanta.
Milwaukee has played a lot better with Middleton and without Parker, who did just get injured again. It is a real risk he is never the same again, but would be an interesting risk for Boston to take.
Dallas never likes to rebuild and someone like Thomas will allow Dirk to have that last hurrah and Thomas is a nice fit with Barnes, Matthews, and Noel. That would be a very interesting team.
Obviously Philly and LAL would want to be going all in, but I can certainly see both of those trades making sense in that scenario as Philly really doesn't need more young players and if LAL keeps its pick and gets someone like Ball, I like Thomas a lot more next to him than Russell (also makes LA a lot more attractive for someone like Paul George).
Denver is on the cusp and is probably ready to make that push, Harris might be a bit too much to give up with Mudiay and Hernangomez, but Mudiay hasn't exactly done much and with Murray (and Thomas) is an odd man out, and while Hernangomez played well this year, he is a rookie at a deep position for the Nuggets. Thomas seems like a good fit there.
New Orleans is looking to win now, that is why they acquired Cousins. You trade your top 3 picks for Thomas, you bring Holiday back, and you have a small backcourt, but one with the talent to match your frontcourt. A mid-tier veteran wing and all of a sudden that team is looking very good (maybe you expand the trade to include Crowder and Thomas for the pick, Moore, and Ajinca - or something like that)
There are similar type reasons for all of those trades and they all make sense in certain circumstances for both teams.