On sale is this Intel NUC extreme barebones mini PC that's a bit larger than your typical Intel NUC and not a bad option if you're after something in this form factor. There's a PCIe slot in this one that can fit small video cards like the RTX 3060 Mini and it has the Intel i7-9750 CPU that's still very capable despite its age.
Like other NUCs you need to supply your own storage and RAM. There's dual channel DDR4 SODIMMs, 2x M.2 NVMe/SATA SSD slots, 2x Thunderbolt 3 ports, HDMI 2.0a, Ethernet and multiple USB ports including USB 3.1 Gen2.
Copied description from previous deal by @Clear(thank you!)
Only concern I would have is the fact it is a 9th gen NUC, where is the current release is 12 gen with significant performance jumps across all areas of the machine.