Catchable Pokemon in Pokemon emerald

regirock)regice)registeel)latias)latiOS)kyogre)groudon)rayquaza)jirachi)deoxys)deoxys(speed forme)mew)celebi)lugia)ho-oh.

zoo3891 says,

here are the ones you can catch in emerald all in able to capture order (zangoose,Roselia,lunatone,meditite,and medicham were notput in this game but those and all of theese are in ruby and Sapphire)

wurmple

poochyena

zigzagoon

lotad

maril

ralts

seedot

wingull

tailow

cascoon

silicoon

slakoth

nincada

skitty

whishmur

aron

makuhita

zubat

sableye

magikarp

tentacool

oddish

gulpin

electrike

plusle

minun

volbeat

illumise

nosepass

numel

torkoal

geodude

koffing

muk

spinda

slugma

skarmory

lombre

swablu

seviper

solrock

machop

spoink

sandshrew

trapinch

claydol

cacnea

pelliper

jigglypuff

bayleaf

linoone

mighteyena

feebas

absol (ftwftwftwftwftw //-*)

gloom

shuppet

vulpix

duskull

chimecho

graveler

horsea

wailmer

staryu

carvanah

corphish

wailord

golbat

chinchou

clamperl

relicanth

claydol

bannette

rayquaza 1

hariyama

lairon

mawhile

groudon 1

kyogre 1

regirock 1

regice 1

registeel 1

deoxys (speed form) 1

mew 1

lugia 1

ho oh 1

and i believe that's all from zoo3891 says.