What a cool thread!
Fave villains? Definitely Elias, Scarface, Alonzo Quinn, Patrick Simmons, the old white-haired HR guy who looked like he swallowed a toad and took "rooftop meetings," Hersh, Ma'am, "Peter Collier," circa 2013-2015 Greer, Kara Stanton, and Link from the Brotherhood.
Disclosure: I figured Clarke Peters, Boris McGiver and Jamie Hector would knock it out of the ballpark since they were so good as Lester Freamon, Lieutenant Marimow and Marlo Stansfield in The Wire
Least-faves? Smirking Mark Snow, "Special Counsel," Martine Broussard (her *NeckSnap* being my all-time fave Root moment), Dominic, Harper, Claire.