For a more detailed introduction to this guide, please read the Retribution Bis guide for the 10-19 bracket. I go into more depth there on stuff like what race you should choose and how to navigate these guides. So, without further ado, the best in slot gear for 50-59 retribution paladins for PvP and PvE in Classic WoW.
Skullflame Shield
2 Hand
Malown's Slam
Dressing Room
If your focus is on Player versus Player action and if we choose from above the most useful in PvP (those that increase stamina, strength, armor, and agility), then your toon should look like this: Retribution Paladin BiS 50-59 PvP.
If you’re in a PvE mindset, then with my chosen recommended best-in-slot items, you would look like this: Retribution Paladin BiS 50-59 PvE.
I built my Classic Retribution set as a mishmash of both worlds centered around an aesthetic I find awesome: Retribution Paladin 50-59 BiS Alternative Gear Set.