I have come to realize that the intersection between "things that can be offered as membership/subscription rewards" and "things that I can actually do or feel comfortable doing" is unfortunately rather small...
Like, I know having a specific Discord server is a popular choice, but I don't have the fucks to want to deal with that, and I'm not yet comfortable (or armed with the fucks) to set up for art streaming.
This is for fandom-related work so for me it's supposed to be more casual anyway... If I were doing something for my original work I'd think more about physical rewards on a regular-ish basis.