Snoke, Admiral Konstantine (from Rebels whom no one mourns), Captain Phasma (only because of her wasted potential), Nute Gunray (I always thought he was poorly written)
@Funtik1312 I just feel like he had wasted potential as a villain and when they brought him back in the fight with ray he didn't so shit honestly he was written well at first but soon became horrible and he's AWFUL in the manga honestly he's poorly written