I don't get the hunger for a GSP fight, I'm sure GSP is still great at almost 40.... but he's almost 40. Khabib beating him now doesn't really do much for me.
Equally not sure who else he would fight. Outside of the same punchers KO chance that McGregor or Justin had, I can't see Tony offering anything fresh and him going the same way as Porier....and he doesn't even have that same chance those first two had either.
Tony makes the most sense though.
Charles Oliveira would make a good scrap too I feel but ranking might be a bit far out.