I think what expansion cards third parties are extremely niche (SDR) or have much better alternatives (to me, and I suspect most others If they thought about it, the 10gbE cards. Get a dock or two for the presumably limited locations you have 10gb infra and the need for it).

What most others have realised is that devices fit the 99% with USB-C, A and HDMI. Or, increasingly, just USB-C as everyone who needs one has a fleet of cheap dongles to provide just the right IO.