I tried some Gator(?) blades (probably have the name wrong), meant to shred leaves in place to feed your lawn. They required some adaptation since they have 3/4"(?) hole instead of the tiny one our tractors use. I remember I got pretty darn close with some standard washers to fill in the gap. They vibrated like crazy. But later I found that you can balance blades pretty well with just a nail or something to hang the blade and a grinder to buzz off excess material, and figured the Gators were vibrating more because they were way out of balance than my crude adaptation. Never got around to balancing them because now I shred my leaves to make compost that I then use on re-seeded portions of the lawn. Works pretty well on my challenging soil.
For everyday use, I haven't ever seen a reason to try anything but the stock blades.