I have joined so many bounty campaigns but found nothing. Only those give me some bounty which i cannot exchange. can somebody please suggest me any valid airdrop or bounty campaign which you think really worth our efforts. 
You have to deal with it or just don't participate if you think it's waste of time or not worth to spend time and effort anymore.
The whole bounty program is not that healthy anymore compare last year. That's the effect of the long term bearish market we had this year. There are lots of ICOs who failed to meet their respective target that's why your reward is just stuck on your wallet waiting for exchange listing and the worst at some of the cases, the devs itself will just stopped the development and quit without a trace.