OpenMC:
https://github.com/openmc-dev/openmc/
OpenMOC:
https://github.com/mit-crpg/OpenMOC
Cardinal:
https://github.com/neams-th-coe/cardinal
MontePy (MCNP Python API):
https://github.com/idaholab/MontePy
PyNE:
https://github.com/pyne/pyne
Neutronics Material Maker:
https://github.com/fusion-energy/neutronics_material_maker
CSG2CSG:
https://github.com/makeclean/csg2csg
OpenMCNP script:
https://github.com/paulromano/openmc/blob/mcnp-import/openmc/model/mcnp.py
Serpent2 Vim Syntax:
https://github.com/gridley/serpent2vimsyntax
MCNP Vim Syntax:
https://github.com/g2boojum/vim-mcnp