There are a few tools I can think of...
1. Milwaukee M18 impact driver and mid torque impact wrench. Both are a bit bulky, but has saved me SOOO much time compared to using hand tools
2. Snap-On Impact sockets. Fit tightly around every fastener and they some off easier (I don't know how) compared to using other impact sockets
3. Snap-On line wrenches. These wrenches have very little play and make doing brake line work a lot easier.
4. Lock and Lube grease coupler. Before using Lock and Lube, I HATED greasing anything. It was messy, the stock grease gun coupler never fit tightly and was a PITA to remove. Now with the Lock and Lube coupler, greasing is 1000x easier and a lot more enjoyable.
5. Yellow Jacket 60440 Heavy Duty Swage/Flare kit. I found this kit at Pawn America for $40. It's originally meant for HVAC, but I use it for brake lines and it's a lot easier to use than the rental flare tools from auto parts stores.