These are list of airdrops and it only lists those upcoming ICOs but it doesn't manage any bounty.

so far I am not satisfied because, for me, it lacks some features which bounty hunters need.

What's the feature that you are looking for? at least state it so you can suggest it to those bounty platforms.

I prefer to search alone in Bounties (Altcoins)

Yes, he can manually search those bounties at that specific section of this forum.