Check out Sapien signature campaign. They have already raised around 2/3 of hard cap, so it should be a good choice. Plus I like GoNetwork project and they are also have a bounty campaign according to dozens of their signatures around this forum.
Excuse me, that I tell it here, but isn't it true, that they shorten bounty pul x12?
If it isn't - forget it, but I heard a lot of negative discussions in their telegram and even topic against sapien on forum.
May be it's not correct, but before choosing this signature, carefully learn about rules of Bounty Campaign