Lots of great ones! Going to go with the three that really amaze me in how well the border work expresses the character (with honorable mention shout out to Atom (JL) for how well the comic art expresses the character):
The well-dressed
Doctor Strange (Avengers), the figure disguised as a card,
Plastic Man (JL), and the fake flesh peeling
Terminator T-800 (Guardian) who prevails over the other Terminator for me due to its subtlety (though the two of them as a set is pretty neat as well). Venom Rocket is pretty neat too, but I could only vote for three.