While developing a prototype for a new game I am working on right now, I decided to use free assets as much as possible. For animations I found Animation Starter Pack by Epic Games very useful. You probably don’t want to use it in your actual game – but it’s really good for answering a lot of questions about your gameplay. And it is a perfect placeholder for future production-quality animations.
I just finished another iteration of my project where paid a lot of attention to polishing the main character animations. This is how it looks so far: