I noticed that the community care a bunch about licensing, and since I moved to Linux I have been paying attention to that a lot, for both games I play and software I use.
So I am making a list of tools I use for my campaigns, in person or online, that still work on Linux, or that I found as an alternative to what I used before.

If you are a forever GM you probably have a licence for FoundryVTT, or are used to other online alternatives, or use those editable PDFs. There are plenty of tools out there for more permissive systems. Like my favourite https://compcon.app/#/ for Lancer.

But I think, on the top of my list, for playing and GMming D&D / Pathfinder PCGen is still king. It might also be a sign that I am old as the tool has been around for a long while.

It works the same on Linux as it works on MacOS or WindowsOS. As long as you have java, you just need to extract the release from github (https://github.com/PCGen/pcgen) and run the '.sh' (or .exe). (make sure you got a file like this pcgen-6.08.00RC10.zip that it comes ready to use, as there is a file called Source Code.tar.gz and you will need to take more steps for it to be usable.

I like that it is straightforward to create a char, PCGen helps you at every step. From this screenshot from the website, you can see there is a checklist "Things to be Done", that reminds you of the things you need to do to a given character.

You can use to manage every aspect of your player, and it gives you options to export if you would rather not use it for playing.

More screenshots here (http://pcgen.org/benefits/screenshots/). The website is old, so it does not have https.

There are also some features for GMing, but I never used, I usually print or use a digital file like PDF or HTML.

http://pcgen.org/benefits/gmgen/

Now, the negatives.

Licensing is a problem, it does not ship with less permissive systems. So you will have to add them yourself.

It comes with a bunch of stuff for Pathfinder, but for D&D you will need to fend for yourself on how to find/install PCGen D&D Data Set

Last, the Data Set file format, and the data format. It is daunting to look at, and a bit tricky to work it. It is just some sort of text file, but it depends on a lot of proper data format and indentation. And as the file grows, it becomes hard to manage. It takes some time to get used to it, if you want to create homebrew classes, items, etc...

Here is the wiki - http://159.203.101.162/w/index.php/Data_LST_Standards

It is nice that someone compiled a bunch of videos helping people do that http://pcgen.org/get-help/videos/

I have nothing to do with the development of the tool, I just use it and wanted to share and read about other people experience, suggestions, workflow, etc...