I know everyone has that one RPG they fell in love with that will always have a special place for them.
Maybe it was never popular. Maybe it was a love it or hate it and had mixed reviews. Maybe it was a product of nostalgia and the time of your life you played it.
For me it was Saga Frontier on the PSX.
Box Art
A game where you pick one of multiple characters and play thru the same game world on each one completing a different quest and seeing things from a different angle.
People would say the story is sparse, for me it was enigmatic and mysterious. People would say the battle system was obtuse, too difficult, or required too much grinding. I loved the challenge and getting wiped by it as a younger version of myself who wasn't ready for that level of difficulty, slowly figuring it out just made it all the more epic.
What's your game?
This is a boring answer, but Super Mario RPG and Chrono Trigger for me. Secondarily, Final Fantasy II (by which I mean IV of course) and III (i.e. VI) and V (i.e. V, because I just played the fan translation, sometime after playing the rest of the aforementioned games).
All of these games are just generally solid narrative experiences with effective and well-designed gameplay, coupled with excellent pixel artwork and music. Not all of them are equal in all regards, of course. But probably most importantly, I played all of them during some of the most formative years of my tastes in videogames.
Not a boring answer, Super Mario RPG was the goat. It took beloved but normally lighthearted and silly characters and put them in an epic story, long before Kingdom Hearts ever did. Blew my mind as a kid.