1/2 impact gun and short, deep, and swivel metric and SAE impact sockets all 6pt. the shop I was in never put them away they were always at hand, breaker bars, long reach pliers are nice, 1/2 extra long and standard length ratchets, hammers (big sledges and even some smaller for axle rebuilds a 5lb short handle does the job nicely), 18 and 24 inch adjustables, long extensions for hard to reach spots, definitely pick up magnets, mirrors and flashlights (you can cheap out just buy LOTS), a creeper, an air hammer and a bigger box to hold it all
Basic hand tools are a must but when you start working on the bigger stuff you will realize what other (bigger) stuff you will need.
The most important tool you can have is your protective equipment (goggles, gloves, face shields, etc. etc.) because with bigger equipment you have a greater risk for injury. Keep a good head and use common sense.