Back in 2017, I bought an Arduboy, a fun little Arduino development system which integrates an ATmega32U4 8-bit CPU, 32 KB of flash storage, 2 KB of RAM, a 128x64 pixel OLED display, some buttons, a speaker, and a battery in a Gameboy-like package.
OpenBSD had an
old Arduino package
available without the
Arduino IDE, and it instead included
for end-users to build off of for compiling projects.
But it was all pretty old and crufty and kind of sucked the fun out of tinkering
with a new piece of hardware.