I built https://zcashdex.com, a work-in-progress dApp to convert ZEC to MATIC, BTC, BCH, and DOGE. Built on Polygon and RenVM, it is open-source and fully decentralized. The backend server submits transactions on behalf of users and takes a small fee in exchange.
A similar app is https://varenx.com/swap. VarenX, however, requires users to have a web3 wallet installed and is less Tor friendly.
Any feedback is appreciated. For instance, I’m thinking of adding support for other bridges and chains, BNB, ETH, SOL, UST, etc.