I have seen a lot threads here about how to choose good bounties. It shows the challenges many of us here are going through in choosing a good bounty. If you really want to maximize your chances of participating in bounties of successful ICOs, i will recommend Bountyhive for you. The success rate of their bounties is very high. Their social media campaign is less stressful because of the absence of weekly reports. They have a limit as to the number of participants in each campaign thereby enabling you to earn a higher income. Although there are certain drawbacks in their processes such as your inability to see your weekly earnings on their spreadsheet, in general their services are really good and i will recommend for everyone
There are no places that post reliable bounties, they just post bounties and then it is up to you to decide which ones that you want to promote, there is no way to tell the best bounties. There are hundreds of bounties on the bounties thread, you just have to go there, look through a couple of them and pick the one that you are most interested in