Of all time
Definition 1 of 1
Pro Tip 1/3Pop Culture
Often used to discuss favorites in music, movies, sports, or art. 
The Beatles are considered some of the best musicians of all time.
Pro Tip 2/3Subjective Opinion
What someone believes is 'of all time' can differ from person to person. 
To me, she's the best actress of all time.
Pro Tip 3/3Historical Reference
Used to compare across different eras, not just the present. 
The pyramids are the most remarkable architectural works of all time.