, I just got an email from a well known high end FPGA board vendor claiming 200 Gbps Digital IO. Yes this is far fetched but I had to know why a respected vendor would make such a claim. The answer turns out to be OCuLink. No, I was unaware that this is a thing but a google search returns plenty of hits. Some variants of the RfSoC have multiple lanes of transceivers that run at 25 Gbps. Connect 8 of these transceivers to an interface and you have 200 Gbps of something. Calling that something digital IO is beyond misleading. PCIe transceivers aren't like Select IO pins. My PCs have spare 4 lane Gen 3 (8 Gbps) slots. What do you think my chances of using one for GPIO are?
BTW, finding OCuLink hits for things that you can connect to your 200 Gbps FPGA board interface is a different proposition. Beware of marketing claims. They can take a kernel of truth and turn it into a fantastical claim... unless you understand the context. The FPGA vendor claims that it can use this interface to connect two boards with a very high speed interface. Now that's believable but practical sustained data rates would likely be no where near 25 GB/s.
 It's curious that these beasts have such limited PL logic clocking support given the capability of the PS hard logic and the transceivers.