https://www.pcgamer.com/division-2-low-level-mods/

A big part of what makes the Division 2 fun is the push to get better loot. But some players have discovered that certain early-game gear is actually a lot more effective than the endgame versions. Specifically, mods that drop while your character is level 16-18 seem to have much more useful stat bonuses, and it’s possible to farm these just by rolling a fresh agent.

Right now, it seems the most effective way to maximize your damage output is taking a new character at level 16 into one of the three Dark Zones to farm green and blue system mods and protocol mods. These can provide 4% or 5% boosts to raw weapon damage—much better than the high-end, high-gear score mods that add tiny boosts to critical hit chances, for instance. The low gear score on early mods doesn’t matter—you can slot up to eight of these into your armor and wind up with an additional 30-40% extra damage.