I'm kinda hoping for Thunderbolt PCIe cards that aren't tied to a specific brand or board. Would be nice to just throw an x4 or x8 card into an existing system

I'm kinda hoping for Thunderbolt PCIe cards that aren't tied to a specific brand or board. Would be nice to just throw an x4 or x8 card into an existing system to get one or two TB3 ports for stuff like external storage.