https://github.com/RazrFalcon/tiny-skia
https://github.com/jrmuizel/raqote
Go:
https://github.com/tdewolff/canvas
https://github.com/femtovg/femtovg
It's a decent starting point for trying to build your own toolkit.
I have recently added a wgpu backend but for now it lives in my fork https://github.com/adamnemecek/femtovg run the demo with `cargo run --example wgpu_demo --release`.
Also join the femtovg discord https://discord.gg/V69VdVu
https://github.com/RazrFalcon/tiny-skia
https://github.com/jrmuizel/raqote
Go:
https://github.com/tdewolff/canvas