Yeah, oddly, spring heels seem to be popular regardless of dive styles. Everyone likes them.
It sounds like you've covered most of the "miracle products" touted here, so I can only offer my list of personal favorite pieces of gear which seem to be unusual across all diver demographics as a whole:
The stainless bolt snap. I use a 3/8" bolt snap on everything. These things are great because they don't wear out or corrode or break, can't accidentally open and entangle or drop expensive gear, and once your fingers get used to using them, can be operated cleanly with one hand in zero vis waters, mud, dark, surge... You name it. One of the best pieces of gear I've ever had. Using the same size on everything allows my fingers to use them intuitively, and allows swap-outs and configuration changes without ever having the wrong size.
Gauges with glass and brass or glass and stainless steel. For me, these include my Suunto D6 and my Thermo (rebadged as Halcyon, DIR Zone, Dive Rite, or whatever) SPG. My diving is brutal, and the toughness of metal and glass, I have found, is far superior to anything made of plastic.
My Scubapro cam bands on my singles rigs. After the dive, lay the rig down on it's face, flip the lever, and the tank comes off. No standing the rig up to change tanks on a rocking boat, having to remove the regulator to get the tank off, etc. I have seen no other cam band design that allows this. No wetting the straps to get the tank to stay, either.
The DIN regulator. Man, these things are great... Solid, never an O-ring problem, and no handle sticking up off the back of the tank to entangle or get beat up.
The convertible tank valve. Problem solved. Never have the wrong kind of valve again. Oh, and Thermo's soft handle, double chroming and high-end feel is fantastic. Virtually bulletproof.
My Heser Backup lights. Three disposable "C" cells, and I never have to think about charging another battery. Will run for something like 55 hours straight, but that really translates to having the capacity to sit on my rig (virtually invisible if clipped off DIR style) for dive after dive after dive with no maintenance required. A year later, when I need them, they work flawlessly, and produce a gorgeous, clear, focused, incredibly bright white light for hours and hours. The best lights I've ever owned. Totally bulletproof. I can't count the number of times I've had to lend one out to a buddy who's got a bigger, badder, more expensive, more impressive-looking light that is flooded, out of battery, or simply not working. I have never had to borrow a light since I purchased these years ago... And I dive virtually every day.
My Hollis M1 mask. This is the first time I've ever gotten a 2-window fit from a frameless, single window mask. The frameless design means that there's no plastic to break, and it folds down super thin if I want to put it in a pocket as a backup. The single window is insanely clear and sits so close to my face that the field of vision is extraordinary. I love the "satin" finished silicone - it doesn't show goo and gunk that always accumulates on dives.
My necklaced backup regulator. This configuration should be a standard in all diving - it completely negates all of the problems associated with "octopuses" and "Air2/3s" and other backup methods. I use a single piece of thick bungie that I purchase in rolls from Dive Gear Express. Simple. Black. Doesn't rot in the sun or fall apart after years of service, diving every day. This material is so good that it's become the stuff of choice in bungie applications on my trucks and boats, too. UV stable and constant exposure to salt water, gasoline and diesel fuel doesn't bother it a bit.
My O'Neill wetsuits. Jack O'Neill invented the wetsuit, and today's ones that his company makes are the only wetsuits I know of that have no straight seams. Like the seams on a basketball or baseball, they curve around the diver's body curves to create a fit that's so good that water exchange is virtually nil. I have dived drysuits and semidrys that exchange more water. Less exchange = a warmer, more comfortable suit, and that equates to more hours in the water.
My dive cart. A few years ago, I took an aluminum fishing cart like this
Reels On Wheels Aluminum Sr. Cart# and added one of these
Roughneck Hi-Top 216-Quart Storage Box-FG3A05H2MICBL at The Home Depot to it. I drilled a single 1/4" hole in each corner to drain water, and it's the best thing since sliced bread. Long walks to the dive site, down the dock, etc. are no longer an issue, and it'll hold all of my gear plus four tanks if I need it to. Usually, what happens is everyone piles their gear on, too, as we walk down the dock. At the boat, I just lift the Rubbermaid tote out of the cart, place that in the boat, and I'm done. Cart stays on the dock 'til I'm back. Boat captains are thrilled to see all of my gear restricted to one place, neat and tidy. After the dive, the whole cart fits nicely in the back of my truck, gear and all. Rinsing is easier, too... Simply fill it with water (it drains slower than a garden hose will fill it) and let it drain out. Love this thing. So does everyone else.
