Kirby 64 is a great example where I played the game so many times that I know where every single crystal shard was as well as all the placements of the enemies in a level. Granted it was a short game but it didn't matter to me.
Some time later I beat Pokemon Yellow enough times to also know where everything was; trainers and items. I also know by heart all the blue orb fragments in Devil May Cry 3 as well as all heart containers pieces and all side quests in Ocarina of Time and Majoras Mask and how to beat all the bosses without taking damage in those 3 games. I feel like I'm forgetting some but I know if I saw the title again I would still remember most stuff in there like a reflex.
What are your list of games that you know only too well?