From month of April, ICO are getting failed and they are not able to pay their bounty hunters. Some of bounty managers transferred tokens but that tokens are not listed on any exchange. I will suggest you to participate in those bounties that are paying in ETH or BTC. Otherwise you will participate in 10 bounty campaigns and there is 50% change that you will get reward from one bounty campaign that will pays you.
That's why you joined on IOVO campaign, which will pay you with ETH and some of their ICO token.
But to let you know, if a token hasn't listed yet on exchange, it's because they are afraif if their token will be worthless on market like this.