Jack i don't know of any site that does, probably is though.

Some changes i know for a fact are to stay a step ahead of the aftermarket replacements, forcing replacement to be bought from the OEM, this includes the blade adaptors.

Most blades today have mulching in mind so they have come up with a lot of contortions trying to evolve a better system of tossing the grass up around to be re-cut. That is probably why most blades now have more then 2 inch's of sharpened area as the being tossed around won't always fall in the 2 inch zone. Some mulching blades are expected to also bag so there goes another set of contortions in an effort to make them work in multiple roles.

Bob