These are some of the projects that I've contributed to.
Mythril is a symbolic executor for the Ethereum bytecode. It comes with batteries included; it can automatically find vulnerabilities, and generate exploits.
Vertigo is a mutation testing tool for Ethereum smart contracts. Mutation testing is a technique to evaluate the quality of unit tests. Even though standard coverage is the most used metric for test quality, mutation testing can provide much more insight.
Tree-sitter-solidity is an incremental parser for the Solidity programming language. The parser is incredibly fast and generates an AST optimised for further analysis.