I can also recommend Lenovo ThinkCentre MiniPCs or similar brands. Those can often be found cheap when companies upgrade their Hardware. These machines are also power efficient when idling, use even less space than a laptop and the case fan is very quiet (which can be annoying with laptops under load).
I'm currently running Syncthing, Forgejo, Pihole, Grafana, a DB, Jellyfin, etc... on a M910 with an i5 (6th or 7th Gen) without problems.
At 100 to 160 used these are a steal, just test the disks before you commit to long term projects with them (some have a fair bit of wear). Its newer cousins quickly climb in price to the $300+ range (still refurb/used)
The bleeding edge of this form factor is the Minisforum MS-01. At almost 500 bucks for the no ram/storage part it's a big performance jump for a large price jump. This isnt a terrible deal if you need dual SFP+ ports (and you might) and a free PCIE slot but it is a large price jump.
I’m pissed at Lenovo for making the perfect machine for a home server, and then cheaping out by not adding the $0.50 M.2 connector on the back of the board. 2xM.2 + 1xSATA requires upgrading to “Tall” Intel NUCs if you want 3 discs.
Yeah I would recommend this too. I've only used Dell Optiplex Micro series, no issues so far. They use external PSU similar to those in laptops, which helps with power efficiency.
Something with 8th gen i5 can be had for about 100-150 USD from ebay, and that's more than powerful enough for nearly all self-hosting needs. Supports 32-64gb of RAM and two SSD.
I second this, I have a 4 node Proxmox cluster running on MFF Optiplexes and it's been great. 32gb of RAM in each and a second USB NIC (bonded with the built-in NIC) makes for a powerful little machine with low power draw in a convenient package.
The Optiplexes look nice, but I went with the Lenovo m720q's for the PCIe slot ... 10Gb dual SFP+ NICs are cheap as chips on eBay and when you can migrate VM's faster it's a nice quality of life improvement for migrating VM's between proxmox nodes.
I'm currently running Syncthing, Forgejo, Pihole, Grafana, a DB, Jellyfin, etc... on a M910 with an i5 (6th or 7th Gen) without problems.