A few weeks ago, I received a private message on Youtube.
"Well, this afternoon I was playing Pokémon Green for laughs and when we sent out a heavily wounded Metapod (you know, with that stupid annoying alarm beep), his cry was Gastly's.,."
I promised them I'd make a video about them all, so for now I'll list some of the Pokémon that sound similar to other Pokémon when on low HP in Red/Blue, and probably use the same base cry. (work in progress)
Kadabra ~ Gastly
Metapod ~ Gastly
Vulpix ~ Graveler
Mew ~ Staryu/Starmie
Parasect ~ Staryu/Starmie
Magneton ~ Gastly