can randomly generate just about ANYTHING. awesome for dms
Tabletop Audio: background music and sound effects for the ambience.
PCGen - a character creation program that handles all the tricky and tedious parts of building characters, including NPCs.
d20pfsrd.com - all the free information you would ever need to play Pathfinder, an alternative to D&D
DiceCloud: Interactive character sheet that can be edit and shared with yourself or others easily. Pulled up anywhere with internet connection on PC, Mac, or mobile device. Use it to also mark down health, death saving throws, spell slots, experience, and more on the fly.
DnDMagic: List all spells currently available from Player’s Handbook and Elemental Evil.
5th Edition Spellbook app: Make spellbooks for all your characters, manage spells, prepare spells. Keep track of Spell Save DC, and Spell Attack bonus on your mobile device.
Squire - Another character creation and management app. Contains most of the basic info and spells already, with options to create spells, items, classes/subclasses, etc. This is the free version, but pro has more options for DMs, including initiative order control.
donjon - Generate random dungeons of any size and CR
