Here's the list of betting exchanges from Peeps' sportsbook thread. I haven't tried them all but I think Fairlay is the best out of them all and probably the closest to Betfair since they offer a wide range of sports. The only thing that sucks is their withdrawal fee ($25~) but it can still go down ($12~) if you earn enough vip points.
Thanks for your answer. This is what I was looking for. Fairlay, looks like the one with the most volume but I'm not too fan of the interface. Exbet, on the other hand, looks about right. Pretty similar to Betfair and it even allows us to connect Sports betting software such as Geektoys through API. The only downside of Exbet is that you can only use BTC. As for Sportx, it allows betting directly from your wallet using Ethereum. Would be great they could implement other protocols such as BSC or Polygon. As for Degens, it doesn't look much appealing and doesn't have enough volume.
While casinos are extremely popular in the market of cryptocurrencies there has not being the same excitement over betting exchanges, some years ago I used fairlay and they were good enough but as you may guess the problem is the volume, so if you are looking to make big bets it is likely you are not going to find what you are looking for, also another issue is that it is likely the majority of those using it are decent at pricing the odds unlikely what happens in betfair, in which there is so much volume that a great deal of volume comes from people that do not know about odds and stuff like that so you can get advantage of it.