The best rpg games like Pokemon FireRed and LeafGreen are Pokemon Emerald, Pokemon Legends: Arceus and Pokemon Red and Blue. Below are 9, each with the reason it is here — and, at the end, what filtering to rpg costs you.
Filtering to RPG means you want progression — a character to build or a party to grow — layered on top of whatever else you liked.
What you get: A reason to keep going after the novelty wears off. RPGs are the genre that reliably converts hours into feeling more capable.
What made Pokemon FireRed and LeafGreen worth playing in the first place is covered on the full list. This page is the rpg part of that answer, and only the rpg part.
The same generation at its most complete, and the Battle Frontier.
The biggest structural change the series has made.
The originals, if you want the thing itself rather than the remake.
The best non-Pokemon monster collector, with a clever type system.
A faithful classic-style monster RPG with modern quality of life.
Collecting plus a team-building puzzle with real strategy.
The Game Boy alternative, with a deeper breeding system.
Straightforward, funny, and full of creatures to catch.
For the team-building endgame, at absurd depth.
Immediacy. Almost every RPG asks for a slow first few hours, and the systems that make hour forty good are the same ones that make hour one a menu.
The full list is on games like Pokemon FireRed and LeafGreen — 9 picks, no genre filter.
Pokemon Emerald. The same generation at its most complete, and the Battle Frontier.
No. Pokemon FireRed and LeafGreen released on the Game Boy Advance, but a recommendation is only useful if you can play it, so the picks above span platforms and eras. What they share is the genre and the reason.
Whether the stats are the point. In an RPG the build decides what you can do; in an action game with stats the build only decides how fast you do it.
No. The picks below span turn-based, real-time and action RPGs, and each one says which it is.
By hand. Each pick was written for the full Pokemon FireRed and LeafGreen list first, on what the game actually does, and this page is the part of that list that is rpg — never a genre tag lookup, which is how "best racing games like Super Mario 64" used to be a page on this site.
Or read the rpg guide for where to start in the genre generally.