All the stuff that isn't good/big enough for a real library.

Amatch is a library for approximate string matching and searching in strings. Several algorithms can be used to do this, and it's also possible to compute a similarity metric number between 0.0 and 1.0 for two given strings.

Library that provides memoziation for methods and functions for Ruby.

This ruby gem provides some useful command line utilities

This library provides structure json logging for our rails projects

This gem displays progress of computations and additional information to the terminal.

Library that provides more mathematical functions/algorithms than standard Ruby.