Very interestiing topic of discussion. Its true many of the ideas of great players may have never been acutally played on the board & so the world remain oblivious until someone else re-discovers to play them (kind of re-inventing the wheel).
Now since (@HorsesGalore) mentioned about Fischer. I am posting two games with somewhat rare opening choices by him.
Excuse me for not putting any annotation- as Fischer's game are way beyond my ability to analyse/comment.
Bobby Fischer had the reputation of playing the same openings. He coined the expression 1 pawn to king 4 is "best by test" and for awhile stuck with that all the time.
When he tried something different in the openings or a "new" variation for him, it was news -- became all the rage for others to try. Often it happened, once Bobby played for him a "new" variation, what were once well respected opening variations were then thought to be suspect or no good ! For instance, when he started playing the White side of the Ruy Lopez Exchange Variation, people started thinking that's a great way to gain the advantage for White.
Do any of you think there may be many more opening ideas / twists Fischer had, but died with him -- as he seldom played chess after winning the world title in 1972 ?