Alright, small-dreams time!
Spontaneous fanart - already achieved! <3 I'd love to see even more of it, but finding someone's taken the time to draw one of my characters is amazing. <3
Cosplay - if I ever see someone dressed as one of my characters, I will break down and cry.
Fanfiction - kind of similar to the first point.
Solid fan-theories - not just a random comment or two on a page, but fans getting into serious discussions of where my comic is going, why a character is doing what they're doing, etc.
... Basically, I just want people to get really engaged in my comic and turn that engagement into some creative output, because that's how I process the things I love.