I haven't played with all of them yet. But so far my favorites are Royal Guard Champion and Boba Fett. Unfortunately they're both expensive to field... but they're fun!

I'm curious what some of your favorite villains are or who you think are top tier?

Some of these are just from theory crafting since some combinations never happened to me in a campaign so far:

1. Jabba - all 4 of his special actions are so good. He forces rebels to hunt him down. If you happen to be running Inspiring Leadership and use Strategic Planning on him, that's 4 extra threat per round. (and he gets half a worth of move action for free! )
2. Agent Blaise - enables threat bomb near the end of a round with his Activate Agent action. Rebels can just sit around and get destroyed. This is similar to "Hasty Ambush" agenda except better (no threat limit, free instead of 2 influence). Oh you can also get 1 threat from his attacks as well (GYY) AND -1 trooper/spy deployment cost during that optional deployment.
3. Greedo - cheap and annoying, if you can play around Slow on the Draw, he's super good.
4. Dengar - there isn't many other ways to get stun and bleed on a hero at the same time.

In Campaign...

• Greedo's Agenda/Summon Card is easily one of the most fun cards in the entire game. (recap, he's threat-free but is linked to a leader. if the leader is defeated he withdraws) So you have this little twerp hiding behind a more competent leader figure (usually another villain if I can work it)
• Hondo's Agenda/Summon Card is also brilliant. He's free, but can't attack, but his normal interaction with crates means you suddenly have a pirate running around the board looting all the boxes. lol
• Inquisitor is just mean. And Royal Guard Champion is a total defensive beast.
• In campaign, we buffed Kayn Somos and Sorin so that their command effects has the same range as a normal Imp Officer. Made them viable (not the most fun, just situationally viable)
• And yeah, having Jabba in a remote corner just issuing commands at the end of each round is very satisfying for the Imp player. lol

Theme-wise, I always enjoy Vader, because he always terrifies new players.

Weiss is fun, too. Fielding a tricked out AT-ST is also a good way to make the Rebels scared.

Gameplay-wise, I'd say I agree with @timmy9921 . Jabba, Blaise, and Dengar all just come with so many options, outside of simply doing damage.

Also, IG-88 is a lot of fun, and I kinda want to break him out again after The Mandalorian. The "Assault" ability makes a lot more sense to me now!

Be it skirmish or campaign, Captain Terro has the psychological effect on my players as being public enemy number one. He's so insanely efficient for his point cost, can't remember the last time I built an Imperial force without including him.