3rd Gen Any good pokemon to catch in the beginning of pokemon emerald?

i started pkm emerald today, and i chose torchic as my starter. i caught a poochyena, and don't know what else to catch. please give me some pkm and where i can find them.

If you're looking for a Water type Pokemon early, you can catch Wingull north of Oldale on Route 103, Lotad on Route 102, or Marill on Route 104. You'll probably find some others that you prefer later on, but they may help you against Roxanne's Rock types.

Other Pokemon that you come across somewhat early on that may be worth a look at are Ralts (Route 102), Shroomish (Petalburg Woods), and Abra (Route 116), all of which you can catch before the first Gym battle.

Zigzagoon is your best choice!!

You find it in the first route of the game xD

Ralts is on route 102 and Shroomish is in Petalburg woods. Both grow up to be really strong Pokemon.

Like the others suggested, Shroomish is a good pick to help you beat the first Gym (be mindful it does gain Fighting-type when it evolves, which may be redundant with your future Combusken/Blaziken) but Lotad is a good choice too, especially being dual Water/Grass will allow it to complement Torchic well.

Ralts is also great, but you may have to switch train it until it learns an actual attack since it's stuck with Growl when you first catch it. Be mindful Ralts is the rarest encounter on Route 102 so you might spend a while looking for it.

Taillow is good imo, although you'd have trouble with it in the first gym. I'd suggest catching a Lotad or Shroomish for the first gym.