Modular forms software

William A. Stein

My Software: Sage -- contains implementations of most modular forms algorithms; I initially started this project to provide an open source home for modular forms software.
HECKE: Modular forms calculator -- I haven't changed this in over 10 years!
Source code for my MAGMA modular forms packages (these are included with MAGMA)
A GP/PARI Hecke operators calculator -- very old (unchanged for over 10 years) and very slow, but easy to change if you an expert with PARI.
Hijikata trace formula
Other People's: Verrill's fundamental domain drawer (local mirror)
Peter Green's Heegner Points Package -- Sage now has better code for computing Heegner points (local mirror)
Qing Liu's Genus Two Reduction (local mirror) -- this is included in Sage now via the genus2reduction command.
ComputeL - Computing special values of L-functions by Tim Dokchitser (local mirror) -- this is also in Sage.