There was the QXL and QXL2, Sinclair QL-compatibles on
an ISA card,
using the PC as a host and for I/O:
http://sinclairql.emuunlim.com/hardware.html
ISTR an Amiga version of something like this but I can't recall any
details, alas.
Has anyone mentioned the Apple-][-on-an-ISA-card yet? There were at least
2 of them, they connected to the disk drives and CGA card too, and let
you run Apple ][ software on a PC system, copy files between PC and Apple
disks, etc.
And I think there was an ARM-2 development system on an ISA card. Never
seen it, though
-tony