Trilium. Tried a bunch but fell in love with this one. Others either didn't have support for inline math or weren't wysiwyg (Joplin). Also easy syncing between computers with its own server in docker, and it even doubles as a web version of the app.

Not exactly self-hosted but, I like UpNote a lot.

It's reasonably simple but, powerful enough for me, and it's fast & intuitive

Notable. Cross platform (no mobile app), sync with cloud drive of your choice, markdown support, easy interface.

Notesnook

VSCodium on the desktop, and Markor on Android. I write everything in markdown, and VSCodium is already where I spend half my time editing and writing code, so it was an easy choice. I also use Vim for quick one-offs, especially if I'm already working on a project with it.

Like others here, I also use Syncthing to keep my notes synced between home server, remote clients, and mobile devices.

Linwood butterfly on f-droid and any app i can type text into

Xed

It opens quickly

I used logseq for my first semester of university and I can't see any reason to switch right now.

It handles markdown and KaTeX, so it handles everything I need really, in a fast simple program.

I use Vscode with markdown preview, with a git repo. The only downside is that Windows incessantly wants to group instances of an application, so it's hard to keep my notes separate from my coding stuff.

Zim.

vimwiki

combined with some bash aliases, neovim config tweaks, and some bash scripts I've cobbled together over time. Then syncthing to share it across my laptop and desktop.

I've tried a few different note taking apps but I always find myself coming back to vimwiki. Its not the most feature rich 'app'. Matter of fact its pretty simplistic but I dont need or want most of the advanced features of other notetaking systems. But what it lacks in features, it makes up for by being a vim plugin. Seriously, I can't handle using non-neovim text editors/note taking apps. Having all of my neovim plugins, and other config tweaks make vimwiki the handsdown winner over the rest.

The missing vimwiki feature for me was a running "to do list" across all of my notes. So I wrote a script that got me the to-do list feature I needed.

I use Joplin mainly, but I've been trying QOwnNotes and Logseq out lately. All of them are pretty good imo

Ghostwriter and syncthing. Ghostwriter really has a good focus mode that really gets me in the right spot for writing. I use Markor if I am on Android and syncthing still works there as well.

on a desktop or laptop I use Emacs org-mode. on my phone I have tried so many options and the best thing that I found for me is Delta chat. I just use the saved notes which is basically an email to myself.

I am currently on Obsidian without any sync at all. Using this in both desktop and mobile.

But used it more in mobile for an offline note-taking app where I could write and read them without any internet connection. Especially to load images from local, make categorization (folders) and more with data I had in my mobile.

While for desktop, I rarely opened it anymore. I am more into VIM with markdown format and then just push it to git host for a quicker note taking.