I’ve used a few online GM tools for campaigns Kanka.io, Masterscreen.app, and ObsidianPortal.com. I even tried using OneNote once, but MS corrupted my campaign file into oblivion. I’m favoring Kanka currently, and I haven’t figured out Masterscreen, yet.
I’m sure there are other GM support tools for campaigns out there, aren’t there?
Since I started using Foundry VTT, I just use that for most of what I need in terms of keeping track of significant NPCs, items, and other notes. I do keep some broader campaign and adventure notes in OneNote as well, but since you’ve been burned by that already once, that’s a nonstarter.
I use Tabletop Simulator which has character sheets and journals for the players and me to use. If I really need to use an external program it’s MS Word that I then export to pdf to import directly into TTS.
That’s how I got all my rulebooks I need into TTS through the use of pdf import.
I actually still use Gametable. Which has somehow fallen to me, not that I can do much with it since I do not pursue coding.
I’ve just started experimenting with AboveVTT. It’s a chrome-extension for DND beyond. I find it pretty easy to use so far: setting up scenes, fog of war. Limited by its dependence on DNDBeyond of course.
You may want to look into Menyr when it releases next year, it’s looking to be pretty amazing, and I can’t wait to use it. It’s going to have map generators!
The simplest, most useful, easy to use tool that has maps, tokens, and fog of war is OwlBear Rodeo. Love it love it love it. No download. Players just jump in by clicking on a link I give them and they just use their browser. Players can be on PC, their phone or tablet. Sure there are plenty of more complex options for this sort of software and I’m sure that once you master them, they are even better, but for having something that you can all just easily use and use well… today… without even going through a bunch of long tutorials… OwlBear Rodeo is king right now for me. I tested it out for my Marvel campaign a couple of times and it works like a charm.
Is this https://www.tabletopsimulator.com/ ?
Looks like Firefox has an addon for AboveVTT Firefox. Very cool.
Wow. Menyr looks amazing.
Gametable?
Yup, you can get it on Steam for $19.99 I believe.
I use one note exclusively. I love it. It’s perfect for me. I work at a company that uses the Microsoft tech stack, so I’m very familiar with their tools. Using it for D&D is pretty natural for me. You got me a little paranoid that my game might get corrupted though, lol.
It’s perfect for taking notes, storing maps and icons (one can store copies of pictures, which you can later download). I write all my campaign stuff and generally share the campaign book with players, putting the GM only stuff behind a password. It’s great for collaborative note taking.
Gametable used to be the king of simple, low to no learning curve virtual table top software. Then the Dev team moved on and it stagnated.
Java based, infinite surface, a few layers, built in chat and dice rolling, shared pogs (avatars) across the network so everyone had a local copy, handy pointer visible over the network so you could point to stuff, basic drawing tools. Very simple and easy to use.
It’s still on Sourceforge if you want to play with the last release.
https://gameniantabele.sourceforge.io/Gametable/Home.html
I use Scrivener for all my notes, planning, etc.
Experimenting with kanka and Chronica for player presentation of data. FoundryVTT is my preferred VTT, but is a little heavy for simple handout and setting references my players want to do between games.
I use Scrivener as well. I’ve used Evernote, Obsidian Portal, and World Anvil, but aside from the online presentation available in the latter pair, it does everything I could want.
Oooh. Scrivener! I just started using that recently for a writing project that I’m working on, and I really like it. Excellent value to cost ratio on that one!
Aside from VTTs:
Donjon
Lots of useful Genrators, including a JSON calendar, an excellent Cavern generator, and a Weather generator.
https://donjon.bin.sh/
DnDSpeak
Book Generator - Dndspeak
Dwarven Automata
https://www.dwarvenautomata.com/
PCGen
> WARNING: This is the bleeding part of the bleeding edge character generation technology. You were warned! 
There is also an Android companion app for full character sheet and stats.
http://pcgen.org/
Others of Note:
Seventh Sanctum
RealmWorks
WorldAnvil
Treepad (or any hierarchical note pad)
WorldMachine (Terrains) - There may still be a free version
I got to digging around in my software and found this useless tidbit.
Box of Flumph
https://www.redblade.org/flumph/
I’ve found a few managers with potential. They each have free and purchase elements to them.
My DM uses Obsidian Portal. He’s a pretty big contributor there.
I was using Campfire until it started deleting entire entries at random. Great potential, too early in development to be trustworthy.
I’m using Scabard.com for my campaigns now. Super easy to use, you can link to other documents you put up, including places, characters, events, items, and others. The creator is active at getting user input on features to add, bug reports, etc. Can’t recommend highly enough!