OK ... I have not made a study of popes but ... here's my top three:
Pope Leo the Great (reign 440-461)
In a letter to the bishops of the Church, in explaining his understanding of Christology that was being disputed at the Council of Chalcedon (451), affirming that Jesus was 'true God and true man' and led to the response that "This is the faith of the apostles!", "Peter has spoken through Leo" and other superlatives ... it was a watershed moment ...
Pope John XXIII (1958-1963)
Elected, aged 75, he was supposed to be a 'caretaker' pope, to hold the post as a safe pair of hands who wouldn't upset any apple-carts while the cardinals figured out their next move ... and then he went and declared a Council – the Second Vatican Council!
He was criticised for speaking to East European communists, but replied that 'whenever I see a brick wall, I think if I can loosen even one little brick' ... he opened dialogues to other communions and other religions, the ecumenical outreach, and laid the foundations for the Church in the modern world. In so doing he triggered a 'liberal v conservative' tussle that's still reverberating today.
A photographer was once setting up a shoot in the Vatican, while the pope was receiving a delegation. So the attendants asked the photographer to take off his shoes. He subsequently dropped a heavy piece of kit on his foot, and was in obvious pain, but didn't make a sound.
Pope John walked across, and said, "Why didn't you just shout 'Oh, shit!' like the rest of us?"
Pope John Paul II
Any pope who gets even a modicum of your approval has got to have done something right!