grex

grex is a CLI tool (and library) that helps to simplify the construction of regular expressions (regex). It does this by generating a single regular expression from user-provided test cases.

This tool includes features such as detection of common prefixes and suffixes, repeated substrings, and much more. Also, grex is capable of converting non-ascii characters, provides case-sensitive and case-insensitive matching, along with capturing and non-capturing groups. The advanced features such as command-line flags or preprocessing methods can be used to create more generalized expressions. 

grex could be highly beneficial for those who want to quickly generate precise regular expressions. It's best used when an initial correct regular expression is needed but may need manual inspection for further optimization and refinements.