The MeLE Quieter2D is a particularly compact and fanless mini-PC. The machine is now available in a new variant with an Intel Celeron N4020 processor with 4 GB of RAM and up to 128 GB of storage.
https://www.notebookcheck.net/MeLE-Quieter-2D-A-new-and-ultra-compact-mini-PC-launches-with-an-M-2-2280-SSD-and-an-Intel-Celeron-N4020.556221.0.html
If this had another ethernet port it could make a good router/NAS with USB storage, but the whole plastic heatsink bit is concerning.