So I can't seem to find anywhere on the web, maybe I'm searching for the wrong words?, but I've tried several different searches on Google, even tried on both Amazon, eBay and a few local sites, without any luck.
I'm looking for similar looking covers for the rear I/O ports on the motherboard, where it includes plugs for the 3.5 mm jacks on the rear I/O.
Some vendors call them dust covers. Try Performance PCs (https://www.performance-pcs.com/), using duct cover in the search box. modDIY has a larger variety but their search engine is pretty bad (it turns fuzzy search to downright hairy) and you have to go through several pages of hits to find them. Since they are Chinese, it will take at least two weeks or more to receive a shipment from them here in the U.S, so there's no telling how long it would take to get to your neck of the world.