Ask HN: Project ideas to level up as a programmer

Hello guys.

I´m searching for good project ideas where I can challenge myself to learn useful skills outside webdev (low level coding, applied math).

My lastest project was a Chip-8 emulator (https://github.com/vitoralmeidasilva/godot-chip8-emulator) and the current one is an implementation of this emulator using PICO-8 (https://twitter.com/vitoralmeidasil/status/967137152080515072).

My main areas of interest are gamedev, AI, graphics, algorithms, low level coding (SO, drivers, kernel).

Thanks for the feedback.