If you're looking for trusted campaigns,then you'll need to work for trusted bounty managers and there are a lot of'em, just that most accept high ranked members only(at least from full member up and in few cases member rank) ,i am talking about the bitcoin paying bounty.
I can rarely see a bitcoin paying bounty nowadays, maybe you mean signature campaign as you can find it here
https://bitcointalk.org/index.php?board=52.0.
So if you want to work with an Altcoin bounty project,you can find a whole lot in the bounty section of the forum.
Be careful with most of'em,they usually end of being a scam,so be reserved on the amount of money you wish to invest with
There are lots of scam right now and bounty campaign is not that profitable because of the current market situation.