I don't know if there's a specific name for them, but there's a cottage industry of fanless "network appliances" based on low-power Intel processors, loosely si

I don't know if there's a specific name for them, but there's a cottage industry of fanless "network appliances" based on low-power Intel processors, loosely similar to Intel NUC, but with different form factors depending on how many Ethernet interfaces they have. Some of the better-known integrators on AliExpress include Topton, Kingnovy, and Qotom, and you'll find a ton of examples if you search AliExpress for "pfSense". There's also an American vendor, Protectli, that offers several variations of this hardware with a warranty, support, and Coreboot firmware (at a premium over AliExpress prices, of course).