You might want to look up Amazix. They're a consultancy that also manages bounty campaigns and maintains a separate site listing all such projects. Same guys behind Bancor bounty campaign last year, so that's a pretty big credential to have as far as bounties go. This isn't exactly what you're looking for since it doesn't have a list of "trusted bounty campaigns" but a list of all the projects it manages. So, if you trust Amazix, then everything on their list will be suitable for you. If you can work within very strict requirements, that is.
Thanks for the response. I will check Amazix, I didn't know about Bancor bounty.
bountyhive is the most user friendly bounty platform so far I have seen.
I think serious bounty hunters have made a small, profitable business in content creation (usually writing content on blogs and sites but also video production)... I've seen now several who started off last year building up a big following for a typical audience of tens of thousands. The "better" bounties tend to be the ones with outsourced management, either to some individuals on this forum or through consultancies like Amazix. By better, I mean those that pay out on quality. This matters because if only good quality creators earn bounties, this can become quite significant as they get a share of stakes rather than a fixed amount. I don't do bounties myself since I don't have any significant social media presence, although I suppose signature campaigns on this forum counts as a type of bounty.