after played progress up to 80% of tech trees, I think I know much enough to suggest some equipment that I think it would be nice to have.
1) Phosphorus/Incendiary granade, working like phosphorus round of gas cannon, damage may not great and not scale so well in late game but it is very useful give temporary bright vision early game when player still not yet access to bio-flare.
2) Gas cannon's dye/smoke rounds and acid rounds. Gas cannon type weapons should have secondary role as utility granade launcher equipment (acid round here also reference to Resident Evil series too)
3) Heavy gas cannon's phosphorus rounds, dye/smoke rounds, and acid rounds, reason similar to 1) and 2)