In high school math class we got paired up for a worksheet and instead of doing any math we spent the hour listing the first 150 Pokemon in numerical order. Been chasing that high ever since
I can name the first 251(gen 1 and 2) by heart and 3 by sight and name, but not by number. It gets a little easier when you realize Gen2 is only 100 pokemon, the smallest Gen. Celebi is #251 and you can work backwards to Mew.
Easy way to solve most gens if you have to fill out a blank sheet - The starters are always grass/fire/water in that order, so your first 9 are always solved. Then the 2 early game bugs(Butterfree and Beedrill/ledyba and spinarak) and HM rat (Rattata/sentret/zigzagoon)and then from there's it's wild west until the end. The pseudo-legendary evo of 3 are with the legendaries, and those come in a set of 3, followed by the 2 title characters plus their hidden legendary so that's the back 9 solved for most gens. Gen 4 has more legendaries/pseudo legendaries so you get 12-15 for free on the back end.
There's some new ones I like but fuck there's over 1000 now. I'm happy just knowing up to 386.
I couldn't number them but give me a long enough time I'd probably get there or close. It's been a long time lol.
In high school we used to keep Pokemon cards in a our binders ordered pokedex style, so knowing them by generation became rote memory when we'd open a dozen packs and have to sort them into sleeves quickly.
Honestly, the names of the newer Pokémon are so dumb that I never tried to remember. The old ones are cool and I'll probably remember them for another decade.
I got into Pokémon when the card game and anime first came to America. I was in jr high school at the time and collected so many of the original cards. Never finished my collection, though.
I got into the Pokémon craze at first, but stopped following it in my later years of high school. I was too busy preparing to be an adult, so I set it aside and forgot about it for years. I didn't even know there were more than 151 Pokémon until over a decade later.
I learned some of the newer generations with Pokémon Go, but I still remember all of the original 151 Pokémon. The newer stuff is just weird to me.
EDIT: I never got into the games, even though they started releasing when I was a teenager. Pokémon Go was actually my first game in the franchise; although I watched my friends play the classic Red and Blue games back in the day.