The best adventure games like Pokemon FireRed and LeafGreen are Pokemon Emerald, Pokemon Legends: Arceus and Pokemon Red and Blue. Below are 7, each with the reason it is here — and, at the end, what filtering to adventure costs you.
Filtering to adventure means the place and the story are what you want back, not the challenge. It is the right filter when the thing you remember is where you were rather than what you did.
What you get: A world with a reason to wander it, and writing that survives being read rather than skipped.
What made Pokemon FireRed and LeafGreen worth playing in the first place is covered on the full list. This page is the adventure part of that answer, and only the adventure 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.
The Game Boy alternative, with a deeper breeding system.
Straightforward, funny, and full of creatures to catch.
Mechanical depth. Several of the best adventure games have combat that is deliberately unsatisfying, because they want your attention somewhere else.
Specifically, these are strong answers for Pokemon FireRed and LeafGreen that are not adventure games, so they are not on this page:
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.
Anywhere the story and the place matter more than the skill ceiling — point-and-click, walking sims, narrative thrillers and most open worlds. The label alone tells you very little, which is why each pick here says what it actually is.
They split hard. Open-world adventures run to a hundred hours; the narrative ones are often finishable in an evening, and the short ones are usually the better written.
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 adventure — 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 adventure guide for where to start in the genre generally.