Whats a good Pokemon emerald team?

Very balanced and strong team. I would suggest going to Lilycove City and visiting the Move Deleter (to the right of Dept. Center). Delete Rock Smash and Dive from Swampert and catch a useless Pokemon (Zigzagoon, a weak Gyarados)to teach the weak HMs. Store in your PC in case the use of HMs comes up, in which case you can just Fly to a nearby city and get it to use the HMs. At your level I am assuming the Elite Four is beaten, so HMs are not very much needed to progress further in the game. Replace Rock Smash and Dive for Ice Beam and Earthquake, or other good Ground/Water/Ice moves. The level of Swampert is very good. I would not suggest leveling it up more, however, until your other Pokemon (Gardevoir, etc.) are just as substantial. All in all, great Pokemon! Just focus on moves. EXCELLENT choices.

I think your Pokemon Team is a very good Pokemon Team for Emerald.

What I would suggest that you do with your Pokemon Team is Level-Up all of your Pokemon to Level 100. What I would also suggest is that you have your Pokemon not know two of the same Type of Move (there is no need for Gardevoir to know Two Psychic Attack Moves). Besides that, your Team looks pretty good. Maybe you could get rid of Rock Smash from Swampert, but that would be it.

Rare Candies can be found throughout the game. If you look closely in every City/Town and on every Route, you should find all of the Rare Candies. You can also obtain Rare Candies by Trade or by a Cheat / Code.

Hope this helps!

Id spread out my hms a little more and not use the same move twice rayquaza and salamance both know fly. Also your in to much of an offensive approach add some defence in their. Speed is also important a high level Ninjask is really useful because of how fast it is.
Other than these things it's a solid team just work up your other Pokemon so you don't have a level 30 with a level 90

First of all,LEVEL UP YOUR GARDEVOIR even Winoa has stronger Pokemon also teach it shockwawe so annoying people cannot avoid getting hit by double team or sand attack
Teach salamence flamethrower,it helps a lot
Give swampert return instead of rock smash it will be powerful as it is your first Pokemon so it likes you more than the others of course
You can also get groudon and kyogre using timerball for the former and dive or net ball for the latter because they can battle for a long time as both have rest to heal themselves up
Oterwise,excellent team and almost unbeatable

First of all GREAT CHOICE OF Pokemon second level up your Pokemon your going to come across a Pokemon who you have a disadvantage against take out rock smash and replace it with earthquake or muddy water take out salamance's fly and replace with flamethrower or dragon claw, take off walrein you already have a water type and replace it with camerupt or magcargo, id take out rayquaza or latios and replace it with a strong grass type like shiftry, replace gardevoir's teleport with future sight and confusion (it is one of the weakest psychic type moves) I understand why you kept it, replace it with shockwave. Replace strength with hydro pump and dive with ice beam (YOU DON'T WANT A STRONG Pokemon THAT ONLY KNOWS TM's THAT IS THE SECOND RULE OF Pokemon, THE FIRST IS DO NOT ONLY LEVEL UP YOUR STARTER)

Sorry to be a bit pushy but hope I helped