Has anyone 3D printed anything for their chair?

I have a printer and my mind is kind of blown with all the things I can print. Has anyone made anything for their chair that worked well?

One thing I have my eye on is this diy power assist project. I don't know anything about materials though so I don't know if it will hold up or. be safe.

One thing I'm definitely printing is this handle extender. One of my chairs I bought second hand and it's a peds chair. It fits me great, but it's really hard for people to push because it's so low.

I'd love to see any 3D printed (or other diy) upgrades you've done!