The only ones that are working are those that act as "crypto bookmakers". All that tried to set up some form of betting exchange face the catch22 problem. They need users to bring volume while they need volume to attract users. Many projects also seem to have come about more as a quick cash grab instead of actually wanting to solve a problem. I'm quite sure it's only a matter of time before there is a crypto Betfair with far lower trading fees compared to existing betting exchanges. It likely will take a while though.