>>39436478The most forgettable mon is probably either Glameow, Or Lumineon.
Glameow because it pretty much only appeared in Pear outside of postgame/post National dex stuff, and Lumineon because it just kinda blends in with the other water types (not to mention Sinnoh had several popular water type lines like the Piplup and Buizel lines. And a popular mythical water type, Manaphy. Most people think of those when they think "Water types from gen 4")