The "Nintendo Games" forum, which includes Retro Game Reviews, has been archived and is now read-only. You cannot post here or create a new thread or review on this forum.
After hours of training my Pokemon in wild grass, I've managed to come across a special Tangela (outside Silver Cave) and a Special Nidorino (somewhere on Kanto - east of Fuscia City).
There's no sure way of doing it though.
Just walk around, get into loads of annoying random battles and just hope for the best. Still, the special colour and flashing intro isn't really worth the bother of looking for them.
Just play the game and if you find one, that's cool, but they're not worth looking for.