searching for a knee brace to wear during yard work

So there are a few options here. It is all dependent on whether you need a lot of support or not. There are the hinged ones which will probably be quite cumbersome if you are planning on bending and picking up etc.
I also listed one with moderate support which is much lighter and will probably do you better for movement sakes. But on the flip side will not provide as much support.
My suggestion is to try the moderate support and see how it goes. If it's just not enough move on to the hinged brace.