Why not make your own?
If you look at the last post, you see a bar of steel attached via "ears" back into the sides of the bucket, with a bolt there. Then, all you need to do is weld onto that bar what ever you can lay your hands on for teeth. make sure that the teeth extend back far enuff to fit under the bucket lip and add a few clips on top to go over the top of that lip.
I cut up some fence posts and used them for teeth. With a 26 HP tractor I'd have to guess hundreds of yards of hard clay and hard-pan have been dug and handled. About 5 building sites have been prepared on steep side hill country, plus many other jobs.
When not needed, just unbolt it.
If you do not have a welder, well, for the price these days, and owning a tractor, you are missing out on what can be made to use for varying jobs. A stick welder will do a lot.