DM Resources

Below are a collection of links that I've found quite valuable for running campaigns in person and online.

Random Generators
Donjon	NPC, Treasure, Story Generator and much more!
Mythweavers Treasure Generator	Encounter and individual item generator
Barrel, Crate and Sack Generator	Random Item generator for barrels, crates, and sacks from WOTC.
Who The F Is My DND Character	A brief one line statement about a character. Includes race, class, origin, and a fun fact about a random character.
Inn/Tavern Generator	Generates name, cost per night, food, etc.
Reference Documents
Hypertext SRD	Rules, feats, classes, skills, monsters, and more. Essentially a quick reference tool.
D and D Wiki	Rules, feats, classes, skills, monsters, and more. Similar to Hypertext SRD, but also includes some homebrew monsters, classes, rules, etc. if you wish to use them.
Wizards of the Coast SRD	SRD Downloads from WoTC
Guides, SRDs, and Spell Lists	Tons of referential info for DMs and PCs
Virtual Tabletops
Roll20	Completely free virtual tabletop, requires registration/login and has some features you can gain with donations.
DM Tools
Encounter Calculator	XP and difficulty calculator, incredibly useful if your party is more/less people than the traditional 4 person party.
Monster Finder	Monster compilaiton that is sortable by CR, size, alignment, subtype, etc.
Ambient Sound Mixer	Different Sounds to Create Ambience for any Situation
Dice Roller
Online Dice Roller	WoTC Online Dice Roller
Alternate Character Sheets
Character Sheets By Class	Character Sheets that can be customized for specific playable classes