Below are some resources for both players and game masters! I’m only including resources I have personal experience with, so if your favourite resource is missing, it is just that I haven’t used it. (Full disclosure, some links on this page are affiliate links)
Other than the first entry, these are general resources that can be used regardless of what system or genre you are playing in:
The official source of online resources for Dungeons and Dragons 5e. It is possible to purchase all of the currently published modules and make them available in a searchable online database. It also has a character builder, campaign management, digital dice, encounter builder, homebrew items and much more. I really enjoy this resource, I subscribe to it monthly and am able to share all of the resources I own with the players in my campaigns.
Online store hosting a variety of material for tabletop RPGs. I’ve purchased materials for a few different systems such as D&D 4e, World of Darkness, Cold Steel Wardens.
Fantasy Name Generators
Random generators for fantasy character names, place names, descriptions, and also names for many things outside of fantasy. Very versatile, I get a lot of use out of this.
Custom design miniatures for your tabletop characters. Lots of options for races, equipment, poses, etc. Recently added the option to fully colour your miniature. It’s a great tool for getting an image to represent your character. The miniatures can be purchased via 3D print on demand or you can purchase the files to print yourself. Subscribers also have the option to create tokens for virtual table tops.
Great source of STL files of characters and monsters for 3D printing.
Generates random NPCs with stats, description, traits, etc. Can be used to quick generate NPCs or PC inspiration.
A website and iPhone/Android app I originally backed on Kickstarter. It allows you to make a pixel art version of your character with the ability to modify your equipment as it changes. It also has some character sheet functionality, but I’ve never used that.
A “virtual table top” (VTT) for playing games digitally. Roll20 has some great services: video chat, mapping, tokens, virtual dice rolling, music, character sheets, etc. I’ve been using this for about the last year to continue my games during the Covid-19 pandemic. Outside of some interesting bugs and issues with the voice/video chat, it’s been an excellent alternative.
Primarily a source of materials for Dungeon Masters, but a great wealth of professional quality adventures and supplements. While his material is specifically marketed for D&D it could definitely be used across different systems. I have personally enjoyed Fantastic Adventures, The Lazy Dungeon Master, and Return of the Lazy Dungeon Master.
An amazing tool that can be used for world building and organizing information about your setting or story. Create linked articles, timelines, maps, etc. I’ve used this to organize some of the information about my primary homebrew world.