Why don't you try to do your own research? There so many bounty on this forum, but you need to see each of bounties here, you can see it on bounty section. If you are interesting to join signature campaign, you can try to join Yumerium bounty just like me. I think that Yumerium look promising to be joined.
Here is the link https://bitcointalk.org/index.php?topic=4465888.0