Most forums have a VIP group/premium subscribers, where people can pay to enter an exclusive user group. I'm working on making a general forum (Ecclesia) and I'm trying to think of perks for our premium user group. The regular perks being a colored username, access to a hidden forum, larger PM space etc. I'm trying to think of new, fun and exciting perks for our VIP, making it worth buying!
I have offered free appeals and rule exemptions for some VIP members. Now granite that's not the smartest thing to do however it did appeal to many people who in the end never actually broke the rules they were exempted from. 😛
Honestly, the VIP package could have tons of things but it depends on the community and if they like the community and are willing to pay; you could offer whatever in the VIP package but that doesn't mean you'll get people to buy it. The community has to have a good reputation and people have to feel like they are wanted, most people won't support the forums they don't like or don't "love" so to speak.
A rather abstract thinking involves bonus on fun and serious aspect. Fun aspect can include what Thomasss said, access to random/crazy section, arcades, games, secret shops, and so on. Serious aspect depends on what the forum is about; maybe you can offer advertisement slot for their websites or allow them to enter in special lottery for cash or vouchers or something like that.
