Ventoy: https://www.ventoy.net/en/index.html  This is handy for having a single USB drive that can boot lots of install or rescue OS images.

blackarch: https://www.blackarch.org/   Installed on an old laptop.  That's a truly immense set of pen testing tools.

Tailscale: https://tailscale.com/   Makes a mesh out of Wireguard connections.  Very slick.  I very quickly bumped into the 20 system limit for the free tier, but that's because I have too many Raspberry Pis.

I was using a hub for Wireguard at Digital Ocean.  That works well enough, but it routes everything though the hub.  Tailscale's setup is easy and clean.