So, since I'm entering the world of being a Divemaster, I've seen it written that it's good to always have spares and repairs. I'm going to put stuff together over time, and thought I'd look for advice from the pros/experienced divers here. Things I'm already planning:

Always have my spare mask with me already
Fin straps
O-rings; duh
Some sort of neoprene repair? Looking for advice...

Okay, CSB time. Found a guy on Craigslist selling a couple of tanks. Turns out he's an old Vietnam Navy Diver. I guess he inherited these, and just wanted to get rid of them. So, I got 2 aluminum 80s in great shape, for $20!

Aquaseal was the one thing I don't have in my save a dive kit. It was recommend so I can patch a small hole in one of my dry gloves instead of using a new pair.

Spare mask strap
Various o rings
Extra hoses (lp hoses for BC inflator and drysuit for me)
Extra battery and tool to open computer for dive computer
Extra silicone neck and wrist seals for drysuit and tool for neck seal
Extra fin straps (even if you have spring straps)

Adjustable wrench and allen wrenches, HP and LP plugs, zip ties, a couple of quart and gallon size zip lock bags.

LP hoses, HP hoses, wrenches, drivers, zip ties, spare reg plugs, mouth pieces, pliers, batteries, assorted o-rings, 1/4 inch bungee, stainless clips, shears, zip cutters...

got damn o-rings will kill a dive quicker than anything so more o-rings.

Orings
Mask
Mask strap
Fin strap with buckles and fin side buckles
Wrenches
Pliers
Channel locks
Dental pick
Allen wrenches
1st stage plugs
Mouth piece
Zip ties
Computer
Computer batteries
Flashlight batteries
Spare flashlight
Spare gloves
Entire set of regs
Weights
Weight pouches