I have recently went for Facebook bounties but these are rare compared to sig bounties.
What are the Facebook bounties going on now? or in the future?
https://exscudo.com/bounty/ I saw this site last night, and I didn`t have time to try nothing from this site. I spent a bit time reading what is this Exscudo and cause i was tired I went to bed after 15 minutes. I don`t know much about them, I just saw your post and I remembered what I saw last night.
Check it out, maybe this is something what you are looking for. Tell us the results, good luck.