Twilight is a layer 2 protocol for building private financial applications, where the validity of computation over encrypted data is proven in zero-knowledge using Bulletproofs. No trusted setup.
zk-Matchbook is such an example of a trustless matching engine for inverse-style perpetual futures for wBTC/USD pair, where orders are settled with a private liquidity pool of wBTC (aka. twilight pool). LPs may lend their wBTC to the pool, without revealing their transactional information to third party observers and traders may buy/sell a leveraged positions from this pool at instant finality.