these Pokemon can be found in the underground right off the bat
Swablu
Absol
Gligar
Scyther
Pinsir
Houndoom
Murkrow
Rhyhorn
Togepi
Munchlax
Lickitung
Magnemite
Ralts
Skorupi
Teddiursa
Magby
Elekid
Swinub
Smoochum
Snorunt
Croagunk
But these ones won't spawn until you receive the National Pokedex
Charmander
Squirtle
Bulbasaur
Cyndaquil
Chikorita
Totodile
Torchic
Treeko
Vulpix
Growlithe
Caterpie
Weedle
