Mym’s Well Products
DM ToolsDonjon RPG Tools: Spell Lists, Monster Lists, Random Dungeon Generator, Random Encounters, and more, for various RPG systems.
Kobold Fight Club: Useful tool to create combat encounters based on difficulty and the xp/cr system in 5E
Monster List by CR & XP
Natural Crit: Template for customizing D&D content, like the Gravity Weaver!