After you pull the plug on Lt. Surge, the next place to go is Lavender Town. The quickest way is through Routes 11 and 12. Unfortunately, a Snorlax blocks Route 11, but you should still go as far as the lookout station, where you'll meet up with one of Professor Oak's aides. After you've talked with him, turn around and head toward Diglett's Cave.
Drowzees are great. They're reasonably sturdy and their Special is very high. They get Psychic (the game's best Psychic-type attack) naturally, along with a couple of status moves, and they really don't need much else. The problem is that Kadabra (or Alakazam) has even better Special and has much better Speed. The choice is yours - fast striker or sturdy support Pokémon?
This area is entirely optional, since you can just use Diglett's Cave to cross back to Route 2 (where you want to be right now) without facing the 10 trainers lurking on Route 11. But you might want to stop by to get yourself a Drowzee, and maybe take down some of the Gamblers for the massive amounts of cash they keep on hand.
NOTE: Checking the lone bush that a Youngster (marked on the map as Trainer #8) is facing will yield an Escape Rope.
The guard house to the east is open, but a sleeping Snorlax is blocking the path. You can go upstairs, though, where you can get the Itemfinder from one of Professor Oak's aides if you have 30 or more Pokémon. That does mean species, by the way (check the "owned" number on your pokedex.) You can also trade a Nidorino for a Nidorina in Red/Blue or a Lickitung for a Dugtrio in Yellow.
Drowzee
Ekans
Pidgeotto
Raticate
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