Whether Judge or a player, the following tools should prove useful for fantasy adventure gaming.
Brave web browser
Brave is similar to Google Chrome or Microsoft Edge, now with built-in security and privacy. Works with all Chrome plugins as the core engine is Chromium. Feels like using the internet back in better days.
Notepad++
Notepad++ example usageThe simplicity of the classic Notepad application, now supporting multiple open files through tabs, automatic backup and recovery, improved search, and much more for advanced users.
Paint.net
All the basic features of Adobe Photoshop offered for free.
SumatraPDF
Sumatra example usageThe best PDF reader by an extraordinary margin, being many times faster than Adobe along every metric. Open an unlimited number of PDFs instantly and scroll anywhere in the document instantly.
Discord
Discord is a type of IRC program used through a web browser or Desktop app. Consider joining the general purpose Pedantic Gaming discord for adventure game discussion, or the Ransack Games discord.
Google docs & Google Sheets
Each offers equivalent functionality to Microsoft Word and Excel, now free and in the cloud. Easily share or collaborate with others. For anything you want to create & share be sure to click the 'Share' button in the upper right to set a desired access level. Typically, you want to share with 'anyone with the link' can view.
StackEdit.io
StackEdit example usageAn online note-taking application that uses Markdown language. Otherwise, similar to Microsoft OneNote or Scrivener. Be sure to use the Workspace setting to automatically sync your files using Dropbox or Google Drive, allowing you to access and edit from any web browser on any computer.
Dropbox
An online solution to automatically synchronize files across multiple devices, such as a phone, tablet, and computer. Supports up to 2 GB of files and up to 3 devices in free mode.
AnyDice
AnyDice example usageSimulates many types of dice rolls, providing graphs and charts of expected probabilities.
donjon
donjon example usageHuge variety of tools for generating treasure, maps, or more for a variety of game systems including AD&D.
Randomly Distribute Numbers
Divide a number into a set of randomized parts, for example to spread 50,000gp across 100 rooms.
Fantasy Name Generators
Fantasy Name Generator example usageName generation website with a huge number of generators.
Dungeon Scrawl
Dungeon Scrawl example usageFree tool for creating dungeon or hex maps. I do not recommend using the newer version just yet. I have recorded a How to Use Dungeon Scrawl V1 video on YouTube, with apologies for the poor quality.
Owlbear Rodeo
Owlbear example usageFree virtual tabletop with fog of war. Doesn't support Hexes, unfortunately.
Rollem Rocks
Rollem Rocks example usageDiscord bot for rolling dice. Greatly preferred in lieu of the never-fixed, incorrect Avrae.