a package Semigroups (former Citrus) for computing with semigroups of transformations and partial permutations, or subsemigroups of regular Rees 0-matrix semigroups, and also with free inverse semigroups,
a package Smallsemi, providing a data library of all semigroups with at most 8 elements,
a package NumericalSgps for computations with numerical semigroups, and