Even though sebastian is passed on I guess even though we didnt see him die but I'd like if a vampire or being from his past returns to get revenge on lizzie just for being associated with him kind of like how old vamps from klaus past tried to kill his family just being related to him. Surely they could pull someone from his merciless days as a pirate. There is this german vampire called gunter coming in but his problem is with alaric if that is to be believed.
Btw side note regarding him but I never understood how he completely didnt know who damon and stefan were, its been established even desicated your brain isnt completely cut off, I mean maybe he couldnt hear from underground until he got that blood so im not too upset I guess, idk i feel it was still a waste of potential.