Looking for free stuff? These resources are all quality. They’re also all free. You can go a long way with the information on this page.
Free tools for structuring adventures and stories
Free Mini-Adventure Packs. Each one of these packs contains a map with description, an NPC and a one-page dungeon you can drop into any adventure without reading pages of lore.
The Big List of RPG Plots. These plots will help you structure stories, and will make it easier for others to improvise.
Free tools for generating names
The Donjon Generator. A long selection of generators for creating dungeons, names and locations. The “weird locations” generator is particularly helpful.
Place Name Generator. This is very helpful for generating evocative place names.
Free tools for generating encounters
Chartopia Generator. This is the oft-overlooked “Donjon of random tables.” Random tables for nearly everything your heart desires.
Kobold Club Encounter Balancer. Use this to balance your encounters. Simply enter the party size and level, and it will output encounters of whatever difficulty you want.
Free tools for generating maps
Watabou City Generator. Still the best in the business, though others are starting to catch up.
Watabou Dungeon Generator. Not as well known as the city generator, but very helpful.