Zarr/Bramma : Toxin

Nukor/Plasmor: Magnetic

I honestly just started using Magnetic on almost everything. I found I wasn’t needing to minmax mod compression, which is what Toxin does by saving you a mod slot. Meanwhile mag/corrosive/heat gives you universal coverage against basically all health types outside of boss fights (where you want Rad, usually, or Blast for Wolf farming). Once the build is done it’s done, no swapping for different factions at all.

Magnetic also has a pretty desirable interaction with Galvanized damage-per-status mods, tacking on an extra element.

Off the top of my head, the big exceptions I personally made were Hek, where I wanted Rad for more boss damage, and Chakkhurr, where I did actually want the extra mod slot for more crit chance.

Melee is a different matter, and where I agree with either more Tox, or potentially pure innate Heat if you want to lock the weapon in as a Heat Inherit endpoint. Tenet Agendus will want Electric though so you’re not stuck with Corrosive.

Plasmor does wonders with magnetic and upfront damage build (a bunch of raw elemental damage + gun CO) as well as toxin + hunter munition bleed build. The second one has more fluidity to it (where the first one struggles a bit) as it runs fire rate and reload speed, the first one gives immense satisfaction of whipping whole corridors of enemies in one shot.

For nukor and arca plasmor, I chose magnetic for both, for different reasons. Nukor is a good primer, and galvanized aptitude works on plasmor even though it’s AoE.

For the others, go with toxin to make viral or corrosive with one mod.