PER compiles every box score stat into one number. League average is 15. Above 20 is All-Star. Above 25 is MVP caliber. Above 30 is historic. Jokić's PER regularly exceeds 30. The limitation: PER doesn't capture defense well. A player can be elite on PER and terrible defensively.
TS% accounts for the value of three-pointers and free throws, unlike basic FG%. League average is ~57%. Above 60% is elite. Above 65% is historic. This is THE efficiency stat. If someone quotes raw FG%, they're using outdated methodology. TS% is the truth.
What percentage of a team's possessions a player uses while on the floor. League average: ~20%. Above 30% means the offense runs through you. SGA at 33% means one-third of all Thunder possessions end with him. High usage + high efficiency = MVP.