Well, for your 33" Snapper Hi-vac mower, try to find the factory made grass catcher, bag, tubes, wing-tips for blade, and the other parts for it. You'll have all you need to catch grass clippings and leaves, etc.
As for the other things, go to a place that sells stuff like you want, look mighty hard at everything, and buy what you need. Otherwise, just make a quick sketch of it, go home, and make one. Thats how us ingenious folks do it!