Each DOOM weapon can hold a total of 2 weapon mods at any given time.
In addition to this, there are weapon modifications which are acquired by finding Field Drones in the game’s singleplayer campaign. DOOM Weapons Guide – Weapons Mods, Mod Upgrades, Mastery Challenges Tips. Taufan99 Mod Team Fortress Mod Technophobia Overdose Temple of Chaos 2 Temple of the Ancients Temple of the Lizard Men 2 Ten Community Project Threshold of Pain Thunderpeak Tiny Pack 1 Titan Titan 2.