I was trying to think of which games created certain mechanics that became popular and copied by future games in the industry.
The most famous one that comes to my mind is Assassin’s Creed, with the tower climbing for map information.
I don’t know what game first came up with it, but Super Mario RPG was the first time I saw timed hits for attack and defense in a JRPG. While the mechanic isn’t exactly ubiquitous it has popped up in a handful of other games over the years and it always reminds me of that game.