Those belt squats are fun. I actually have a log chain bar for this purpose, though there is not a ton of advantage over just hooking weight on a belt as these puppies are pretty hard to do, and though the log chain bar will allow for loads up to around... oh, a crap ton of weight, I can't move that much weight

Harnesses are fun. I think APT regularly runs a special where you buy one and get one free. We have an ironmind harness at our gym and it is absolutely the cadillac of harnesses, lol. Also costs as much as a cadillac