Badges and Stickers
Both badges and stickers are good idea.
They're even better when you can tie it into a topical event/occurance.
Why not give all members a virtual badge that states their position (and the community's position) on a relevant topic. This might be a controversial issue in the sector. Members can display the badges on their social media accounts.
It's all useful for group bonding.
Aside, if you're not reading the StackExchange blog yet, you really should be. And here's a bonus interview we did with the StackExchange team a few months ago.