So I just started using UE5 for short film making and I’m trying to add animations to a character. If I switch to “Use Animation Asset” for the “Animation Mode” I only get the default 11 animations included and cannot select any of the others I have in various folders. I’m new to all of this
Have you imported your animations into the project? 
Yes I have. They’re working just fine when I double click on them to preview as well.
You can make it show up by clicking on the gear icon next to the search bar and ticking the checkbox next to the Allow Incompatible Skeletons option (which is on the very bottom)
However, your animation asset will show up as blank when you do so. So what’s going on in your case is that you either didn’t properly import the animation assets, or you’re trying to use an animation on an incompatible skeleton.
Hope this helps! 