Blank Wood Duct Caps (for closed off ducts in floor)

We had our crawl space forced air furnace with floor ducts (bad idea to put a furnace in a 3-4 foot crawl space) decommissioned and replaced with attic furnace with wall / ceiling ducts.

Now we have unconnected floor ducts with metal registers and magnetic covers. The magnetic stuff is tacky at best. Been searching for a wood register with no fins or ducts – just blank. Utterly simple to me. Like one of those blank switch plates. Then it could be stained to a close match to the hardwood floor.

Able to find wood vent registers evertywhere but no blank caps. Did find some links to make my own (make one with vent holes but don’t cut the vent holes) but don’t have the tools or diy for that is a bit advanced.

Links, ideas or tips would be most appreciated.