I've really liked using onenote, but would like a FOSS alternative if there is one that replicates the experience. I don't need any syncing abilities, since I prefer to store locally.

Since Joplin got a shoutout here, i feel like Notesnook should be mentioned as well – feels more polished and is potentially a good e2ee Evernote alternative. Not sure about OneNote tho

Also a big fan of notesnook. Just miss some formatting extensions which Osidian's community provides.

go

I use Obsidian. It is simple and easy to use but very feature filled. It uses Markdown and stores files locally.

Not everybody will mind but Obsidian isn't FOSS unfortunately. That said I think their business model is very reasonable and import/export is super easy because everything is markdown. Some FOSS alternatives are Trillium and Logseq.
- I've been very happy with logseq and use org as the file format since I also use emacs and orgmode. But having logseq being a dedicated notes solution on desktop and mobile has been great.
  
  I know that OP isn't interested in syncing, but another FOSS application I use in conjuction is Syncthing. I use it to sync between my devices, while still being local (to my own devices).

Joplin is great. It can't do the handwritten notes like onenote as far as I know, but otherwise I think it's got pretty good feature parity. You can sync it using an existing nextcloud, WebDAV, or even onedrive or dropbox if you don't want to deal with the hassle of self-hosting at all.

I see Joplin being recommended a lot and with some onenote migration tools I think I'm leaning towards it. I use onenote to copy paste images and then type in notes, but also use a drawing tablet to write some short notes on images and highlight stuff; sometimes mouse if I'm too lazy to connect the tablet. Is Joplin able to do that? I don't do like entire pages of handwritten notes.
- Yeah you can copy and paste images into a note just fine.

Xournal++ is the most similar in intention I believe.

I personally use a combination of logseq (FOSS) and obsidian (not FOSS, freemium I think). Obsidian is currently better on the tablet due to some particularly well put together plugins and a recent feature update but I'd like to move completely to logseq long term. However, if you're looking for a touch centric experience it's hard to deny that obsidian is the best in the ecosystem.

Of those options which would you recommend for a desktop user where majority of interfacing will be with keyboard and mouse? Particularly if I'm looking to migrate over lot of data from onenote to it.
- Looks like exporting from OneNote to markdown is not ideal, so if you're not willing to go the copy-paste route or manual entry you may want to look elsewhere. That said I think it's a toss up between logseq and obsidian. Of course one is FOSS and one is not so keep that in mind if it's a dealbreaker. They take slightly different approaches to the minimum size of a piece of content. Obsidian uses a page format (like joplin) while logseq is indexing on something closer in spirit to a paragraph (though these can be of arbitrary length). This has a couple of unique benefits like being able to automate the creation of flashcards and similar review tools. Both have vibrant plugin communities.

What about Zim? I have been using Zim for a few months. I had used Joplin in the past, and I don't remember any issues but for some reason the most recent time I reloaded/distrohopped I installed Zim instead. The one feature I like about Zim is tables in my notes.

Zim is great for laptops and desktops and large note collections. I am not sure it has a mobile client. It does not have builtin sync either. Could probably sync just the file tree though. I use Zim and Joplin all the time but for different things.
- Ah, That's why I asked - It has been a long time since I used Joplin, and did not use any of those features when I did (um, I may have had Joplin on my phone tho, but I don't remmeber if I synced between phone and laptop Joplin)
Zim is really tops. OP, I don't know that there is a migration tool, but you should give Zim Wiki a look for sure.

I'm running Joplin syncing through a nextcloud. Works solid for 2 years now.

I went from Evernote to Joplin (in its early days) and then onto Emacs with org-mode. I realise that is a big leap, but it has IMHO been worth the effort.

@NightOwl As already said, not foss, but obsidian is a really good option. I moved away from Onenot and Notion, and all my files are local in markdown.

I currently use Joplin, which I sync using Backblaze B2 (which is S3-compatible).

I'll throw out there that Emacs org-mode is an incredibly robust solution for this, although it may be a bit overkill for your needs (and may send you down an Emacs rabbit hole).

At least for me, it's gotten to the point that my entire life can be summarized in a giant pile of *.org files. I highly recommend it

I really like Trilium. It's basically a FOSS Obsidian. It does not have a phone app but the web interface is mobile-friendly.

Nice, thank you for this recommendation! I am looking for an OpenSource replacement for Obsidian. Just miss a mobile app here.

Standard Notes is pretty great

I wanted to like Joplin but I really wasn’t a fan of the iOS app. Check out Logseq, it’s just about to hit v1.0 and it’s already pretty great experience. I left obsidian for it.

Standard notes

I use Joplin. FOSS, solid apps. And then I use Logseq for my personal knowledge management.

What do you get out of logseq that you don't get out of Joplin. I mostly use Joplin for offloading stuff I know i'm not going to remember so I can look it up later.
- Logseq is where I put the Zettelkasten method to use. Joplin is mostly for quick fleeting notes or stuff for my novels.

Ive recently started using JTX board...it symcs with Nextcloud and DavX5. It has a To-Do list as well.

I have resigned to keep at the moment. I was a Joplin user for a few years and installed a server on my nas as a docker. Eventually the app said I needed to update the server to continue syncing. For me setting up the docker was a pain in the ass so when it asked me to update I just gave up

No offense but I'm seriously stumped on what makes OneNote good? I have to use OneNote for work and I shift through the Windows Office LTSC 2021 version of it, the web app on various browsers, and the android app. They all suck, getting the app to force sync takes to many steps and I'm having to do it frequently, the lack of code snippet support, the weird text boxes you drop everywhere if your not clicking inside the box, keyboard shortcuts are very lacking. Am I using it wrong or something? What makes it a good note taking app for you?

Handwriting. I've not found a good linux or Foss alternative that lets you have an organized collection of hand written notes. It's not necessary for everyone, but it's rather useful for a lot of people.
I guess it was because I didn't use it through the browser or the windows store version. I started using it from office long time ago, and continued using it preferring to get the exe version from onenote.com/download.

Never bothered with syncing since I don't use a windows account.

I use vimwiki. If you are on linux you can set up a workflow: spawn a terminal, launch neovim, and using plugins, use a keyboard shortcut (eg <leader>vw) to launch into your main personal wiki page. If you host that index on a syncthing folder, you have auto sync'd notes across all your linux instances. You can configure your pages to be autosaved as markdown files.

I use qownnotes in combination with nextcloud.