zorl'ok or something along that
Feng the Accursed, he may not be the toughest of them all but the fight is fun and has some interesting mechanics.
Elegon Normal is good fight.
Did amber shaper last night actually, got reshape life on myself for the entirety of P2 and then with that the first person in P3 to have it. 6 times in a row or around that, was amazing. 1mil crits by the end of the fight is also too good. Really actually enjoyed it to add to my original bosses.
2: Blade Lord
3: Stoneguard (mostly because it felt very rewarding once i learned to tank it, tanking it on 25m was even that much better.)
Feng HC, Elegon HC.
I don't feel any other boss compares to these two.
I didn't like the "feel" of HoF. And Garalon is just a horrible boss imo. First 2 were probably most fun.
Terrace is in general cool, but nothing special to point out.
"DPS is science, healing is art, tanking is strategy."