Test Polynomials for Galois Groups - A table of polynomials for Galois groups over the rational numbers with degree up to 9. The table includes links to additional information for each equation.
Small Even Order Groups - Generators for small even ordered groups from 1 to 1000. Files use gzipped extensions and require downloading.
ATLAS of Finite Group Representations - Representations of many finite simple groups and related groups such as covering groups and automorphism groups of simple groups. Available by FTP in alternative formats: Meataxe ASCII, Meataxe binary, and GAP.
Groups of Small Order - A list of isomorphism classes and further information on groups of order up to 30, by John Pedersen, University of South Florida.