OpenBSD will run on almost everything, just the kernel does not contain binary blobs in order to support absolutely everything. You can if you want download non free firmware and install it yourself painlessly if the installer doesn't automagically find your drivers. I have yet to find a machine where I've had to do this though, since I usually buy no-name Taiwanese hardware which is always supported by *BSD because the manufacturers give out hardware documentation to them

That is still the state linux is in. The difference is with openbsd, 99% of hardware is supported, and the 1% has no driver. In linux, 99% of hardware is supported, and the 1% has a buggy broken driver that will crash your kernel. Buying dodgy hardware is a bad idea regardless of your OS.