Until Arceus came along and finally did what Pokemon should have been doing a long time ago, it was Pokemon Snap. Arceus is great, but it’s also the bare minimum of what I think the series should be. I would hope that Palworld has set a fire under Nintendo and GameFreak’s ass to get them to make something that actually brings the series forward instead of keeping it mired in game design from a bygone era.

Crystal!

Emerald holds a special place in my heart. Omega Ruby got me back into Pokemon and to this day is my favorite. I’m currently playing through every generation, but no other region hits harder that Hoenn

Ruby and Sapphire, 100% because of nostalgia as I haven’t played either in 20+ years - those were the last games my grandpa gifted me so they hold tremendous sentimental value.
Gold and Silver would be close seconds, since my sister and I played those games when growing up and I have great memories from back then.

Pokémon Mystery Dungeon: Explorers of Sky

In terms of mainline games though, I’d probably have to go with Blue version, since it’s the one I’ve spent the most time with over the years

I played Gen 1 as a kid and didn’t play Pokemon again til Black and White. It was an amazing leap to see the first and last pixel animated mainline Pokemon games, and both had their own unique set of 150 Pokemon. It’s like a showcase of how much the series had grown.

Incidentally, it was the last mainline Pokemon game I actually enjoyed.

Emerald, leaf green, and gold?yellow?

Pokemon Master Trainer

I put the most hours into soul silver, but god, I fucking loved Prism

For Nostalgia? Red/Blue and Gold/Silver.

HG/SS and B/W are up there too for different reasons.

And funnily enough, I actually enjoyed S/V quite a bit. Aside from the lull between gens 6 through 8ish, there’s a lot to like throughout the series imo. A lot to dislike too, but still a lot to like.

Crystal (mostly nostalgia), Emerald, and Conquest

For me i would say silver for the nostalgia factor, Also silver (and gold) were compatible with the original black/white gb so Even more nostagic than Crystal

I would like to say leaf green just because I played it later on and the little clubhouse you could make was cool, I recently started trying to replay one of each generation like yellow, crystal, and now emerald but man I just want to power through them but you have to grind to level up and i get sleepy

Um… one of the later ones for the 3DS. But I think these new ones coming out soon will be super awesome. I don’t play many Pokemon games though.

I’ve played Blue, emerald, black? For 3ds? And that’s it.

I have a soft spot for Crystal, in terms of the official series.

If we include rom hacks, Crystal Clear is great, and I’m really enjoying Pokemon Emerald Rogue these days.