We have this thread at least twice a month:
>Kanto: Agatha
She's definitely memorable, just less than her peers for a reason or the other.
>Jotho: Karen, Will
Will is an obvious choice, especially since a lot of kids (read: me and my friends) thought it was cool that he was in both the Sinnoh and Jotho league. Karen is also one of the most forgotten in spite of the small group of karenfag that are trying to jump on the mature lady R34 train, in spite of the absolute lack of characterization of their waifu. Hell, the most notable trait of Karen is the condom belt looking accesory
>Hoenn: Glacia, Sydney
A bit more memorable than both Karen and Will, still rather obscure, especially Glacia that feels like a fusion between Agatha and Lorelei (which is kinda good to make her memorable tho). Glacia is surprisingly more loved than Karen in the porn world too.
>Sinnoh: Lucian, Bertha, Aaron
Aside from Lucian, that a lot of people mistook for Will, Bertha and especially Aaron aren't that forgettable, it's just that Cynthia overshadow all of them.
>Unova: the last elite 4, Marshall, Shauntal, Caitlin
Objectively the most forgettable elite 4, they're more known for the stuff that surround them instead of their characterization, hell, I can't even remember the name of one and I don't want to Google it. They suffer a lot from not having personality in a game were gym leaders and other characters were flashed out really well. Even considering the postgame and their absurd designs they were pretty much cardboards with shitty teams, with only Shauntal notable for being the Pokémon big tiddied goth GF for one gen (and getting forgotten the next gen in favor of a rando NPC that isn't even big tiddied) and Caitlin that whole personality was being from the fourth Gen Battle Frontier. Hell, Thornton has been far more popular than these 4 combined.