Bobcat does make a grapple that will bolt on to most of their buckets. That is probably the simplest solution.
I have a 72" construction grapple which works great for lots of tasks, especially concrete, rocks etc. It can also double as a dirt, sand or rock bucket in a pinch but can't hold as much as a bucket and the grapple gets in the way for some tasks and less visibility. However, they weigh up to 900-1000 lbs and heavy. Takes a lot of abuse to damage one. I use it mostly on my S300 skidsteer. New ones in the $3.5-4K range.
I also have a utility grapple which is much lighter in weight and works just fine for picking up brush, down trees, hay etc. I use it frequently for pick up cedar trees after I shear them on the TC or my JD 3720 CUT. I like it for the cedar trees and brush. The branches can get caught between the teeth. Easy to remove my just laying the tines on the ground, back up and they come off easily. Can be used to pick up large round hay bales. This is probably the cheapest option but would not recommend it for trying to dig roots or stumps out of the ground. The tines are fairly strong but if put all the lift on 1 or 2 tines, they can be bent. I have used my for 2 years with no bent tines. My brother used it for 20 minutes on the S300 and bent one tine on a stump. Idiot. Bent it back in a press. New around $2k or less. Weigh around 400 lbs for 72".
Root grapple is probably best choice for just just brush and tree work. Could do some rock, cement but not as HD and can't pick up the small stuff. Can sift the dirt out of the roots and can dig a little in the ground. They tend to have the largest grapple opening to get brush and trees in the grapple. Don't own one. I use the construction bucket or utility grapple because they fit my needs better. I would tend to favor the root grapple with more of a flat bottom with teeth since it could be used for other uses to carry stuff. The Westendorf style with the more vertical teeth and grapple seems limited for other uses and seems dedicated for just brush or trees.