Which vendors give free access to firmware updates? And under what terms?

PoC and test-equipment time is coming up again, but I don't always know what to expect from vendors we haven't used, or haven't used recently. Can we make a list of vendors who offer access to updates without current maintenance contract, and the terms under which those updates are offered?

For example, I think it's still true that Cisco offers an updates without contract when a CVE has been identified in a previous version. I hear they need to be contacted about it specifically in order to release a given update to a given login account, but I don't have any first-hand experience with that. Even setting up and verifying an account is more trouble than just downloading files.