DietPi! It's one the most resource efficient distros that is easy to set up. It's ideal for single board computers and virtual machines, so I use it as a low-overhead Docker host on my Raspberry Pis. The dietpi-software tool installs optimized versions of most software you might use for SBC projects, but if it doesn't have what you're looking for, you can also use APT to install packages from the Debian ARM/ Raspbian repos.