GAMESS (US)
The Iowa State GAMESS program provides molecular electronic-structure methods from Hartree–Fock and DFT to multiconfigurational and correlated wavefunctions.
Where it fits
Broad molecular research and teaching with a no-cost research-group licence.
Limits and practical considerations
GAMESS (US) and GAMESS-UK are distinct programs; binary releases and source builds have different platform coverage.
Licensing and access
No-cost registration-based licence for academic and industrial users, with redistribution restrictions; source availability is not open-source licensing.
Official documentation and project