One of the best bounties this 2018 which started last September is the bounty from TAUcoin. This is one of the promising cryptocurrencies around and they are very generous in giving bounties as long as you are active. It uses POT (Proof of transaction) which is an experimental consensus algorithm to determine which mining club will generate the next block, the more transaction history weight in the club, the high probability to get new block. TAU proposes a fast, fair and secure currency without inflation. You guys should check it out.