There probably will never be a list of all the cables that will work. Nevertheless, I found out on Friday that we have tested some more cables with the Intel® Ethernet Server Adapter X520 Series. The support page cable list will be updated to include 8m & 7m cables from Panduit, 8m & 1m cables from FCI, and 7m & 1m cables from Volex. As you have observed, lots of cables will work. The posted lists share the cables and lengths tested by Intel. We do not have a list of all the cables that will work.
But Intel does have a list of acceptable cable manufacturer OUI responses embedded in the BIOS of the X520. If it is not in the list you respond with an "unknown". Rather than having all of us in the field buy dozens of different manufacturers cables to see what is on the embedded list, just post the codes and make a big disclamer that only tested cables are officially supported by Intel. Ones not on the list can submit to be on the next BIOS release orpay a fee to be supported and/or tested.
This same problem exists on your previous generation AF DA card but it's allowed list and tested list is even smaller. So unless you update the BIOS it is going to be a hit or miss for all of your integrators connecting to others switches, servers and solutions.
Not trying to be argumentative, just pointing out this cable support problem invariably shows up as a post sale problem after the customer purchased his own cables at a "better price than yours". To tell you the truth I cannot answer his question as to what will work. But I have had to pull the Intel cards and sell Qlogic cards beause Qlogic could confirm a HP cable would work with their card. Not my preference and I am sure not Intels.
I have a workaround for Linux users but nothing for Windows users. Unfortunately the majority of users are Windows users
I did some checking into how are driver checks for cable types. The latest driver software should work with all SFP+ Direct Attach Passive Fiber cables. There was an issue with some passive cables being blocked with the original drivers for the Intel® 10 Gigabit AF DA Dual Port Server Adapter.
When the Intel 10 Gigabit AF DA Dual Port Server Adapter was first released, the bit that identified a passive cable was not yet defined in the standard. The standard was updated since then, and the driver has been updated accordingly. Therefore, the HP cables (or any other brand of passive cables) will not be blocked by the latest drivers.
If anyone is having trouble with a direct attach cable, please try the latest driver.
In the case of the Intel® Ethernet Server Adapter X520 Series, blocking passive cables was never an issue since those adapters were released after the standard was updated. I expect the compatible cable list to have additional cables added over the coming months; however, you should be able to choose any brand of cable that you want to use.