In emerald, I recommend you catch Rayquaza, Kyogre, and Groudon ASAP. Get a metang from Stevens house after the okemon league and train it to lvl 80+. Mine is lvl88 and my best non-legendary. Also, Try and get a Swampert, (lvl80+) from a trade or begin the game with it. Also try and get a Blazken. A good, non legendary non starter Pokemon is Salmence. Catch a Bagon in Meteor falls and train it to a high level.
This is my current party:
Blazken-Fire/fighting lvl 89
Swampert-Water/Ground lvl 89
Rayquaza-Dragon/Flying lvl 89
Kyogre-Water lvl 89
Salmence-Dragon/Flying lvl 88
Metagross-Steel/Psychic lvl 88
You may not want a Salmence since you have Rayqaza, and Metagross starts lvl5 so needs a lot of training, but it has high attack, and defence due to its steel type, and high speed, SA, and SD due to it's Psychic type. Steel are also rare and have many resistances.
another team that is good is:
Electrode
Swampert
Grumpig
Breloom
Torkoal
Rayquaza
Yes, You can catch Groudon in Pokemon Emerald.
You can't catch one in Pokemon Emerald.
No you cannot catch Entei in Pokemon Emerald.
You can't catch a Bellsprot in Pokemon Emerald. You trade it from Pokemon Leafgreen!
There are many Pokemon you catch that are similar in sapphire and emerald but there are many Pokemon emerald can only get and not sapphire.
Yes, You can catch Groudon in Pokemon Emerald.
You can't catch one in Pokemon Emerald.
No you cannot catch Entei in Pokemon Emerald.
You can't catch a Bellsprot in Pokemon Emerald. You trade it from Pokemon Leafgreen!
There are many Pokemon you catch that are similar in sapphire and emerald but there are many Pokemon emerald can only get and not sapphire.
Cressilia is a 4th generation Pokemon so you can't catch it in Pokemon Emerald.
You can't catch or obtain other trainers Pokemon in emerald.
No you cannot catch Celebi in Pokemon Emerald.
you cant. You can only catch it in Pokemon emerald, but, you cant catch latias in emerald.
You can onl catch LUNATONE in SAPPHIRE but you can catch solrock in emerald
imposible there is no such thing as bonsly in Pokemon emerald
You cannot catch Entie in Pokemon Emerald. You can catch Entie in FireRed, LeafGreen, HeartGold, and SoulSilver. You can trade Entie to Emerald from FireRed and LeafGreen.