I use yWriter, Scrivener (not FOSS, but worth the little money it costs) and LibreOffice. I feel well prepared for any writing.

I've been enjoying novelWriter for a few months now.

It's FOSS, works on every OS, and is created by a writer who was frustrated with the other options available. She and another writer co-designed it initially, and there's a respectably sized community built up around it at this point. It's got the kinds of features that writers actually need, and avoids bloat. So they say, and in my experience that's certainly been the case.

NeoVim

Celtx used to be a great Foss desktop screenwriting application, based on Firefox. Eventually they tried to go web based, and I had to move over to the closed sourced, industry standard, final draft when my work started getting produced.

Now there are a thousand open source screenwriting tools, and not one that I like.

Apostrophe for offline use, and, unfortunately not FOSS, overleaf (latex) for online use. I really need to find a FOSS replacement...

Another tool is yWriter.

This isn’t a tool for everyone, because it is research-first focused.

What I mean by that is that it’s a little clunky because background/research data is meant to go into it first, and then you are supposed to lean on that content to write your book second.

So for a non-fiction book, you would add all the data and facts and references, for a fiction book you would put in all of the important characters and plot points and things that the characters interact with.

This is so you always have a body of references to work off of so you don’t introduce inconsistencies.

Some people might find this software useful because assembling and fleshing out the underlying data is loads of fun and/or how they prep. Others might need this feature just to keep track of everything that goes into their book, as they might not be able to keep track of things like character quirks very easily in their head.

YMMV.

I really like QuollWriter.

On the simple side, Ghostwriter is a markdown editor with no frills.

NeoVim i write in a text file open in libreoffice and resave in the format i wantedn

I use a text editor called micro for most writing tasks. It's simple enough that it doesn't distract me, but flexible enough that I can use it for most things. Creative writing, code, notes all the same application.

Before I heard of micro, I was just using nano. Same thing, different key bindings. Though until recently I didn't know it could be setup to show line numbers. Which is why I liked micro when I found it.

A program I have used to help with outlining is Manuskript. It has a series of questions it will ask you to help with character and world building. It also has a section to write the novel in and keep track of chapters.

It is a bit on the older side, with the last update about a year and a half ago. It is available on Flathub if you want to take a look: https://flathub.org/apps/ch.theologeek.Manuskript

I just started a novel project a few weeks ago and have been using scrivener because it's just what I saw recommended the most. But now I've switched to linux and have been looking for FOSS linux-native alternatives so this is perfectly timed. I tried anytype briefly but it feels like it's designed for programmers. By which I mean it's extremely powerful and flexible, but just doing simple shit like creating a bunch of pages in a tree structure requires an hour of hunting and watching tutorial videos.

I like the look of novelwriter that someone else linked, gonna give that a shot.

I'm writing a novel in Obsidian and it works great. Currently closing on 70k words and it's just as fast as a file with 50 words in it. I also like that it's a simple markdown file which I can easily back up anywhere and open with anything. It can also organize multiple files and link to them if needed, which is nice when starting out if you use the snowflake method.