Most over-used pokemon

[Elegantensue]

I must say that there are quite a few overused pokemon from gen 3, i'd say blaziken, swampert, rayquaza, flygon, salamence, metagross, ninjask (with speed boost), gardevoir, breloom and even groudon. Some less obvious, but probably still overused pokemon are altaria, skarmory, aggron, absol, slaking and ludicolo. Although most of the other pokemon are highly underused, for example kyogre is amazing, it has pretty much the same movepool as groudon just with different types, and the types really work to kyogre's advantage, plus sheer cold is the only OHKO that will work on any type. I don't think i've seen anyone use a mawile, torkoal, grumpig, solrock/lunatone, glalie or tropius plus several others, they really deserve to be noticed!

[PopPrincess_Lyra]

Hm. In my theory... probably Gardevoir, but I never used it, nya~

[Pilpulp]

In my opinion the only good pokemon in the game were Mudkip or Torchic I personally was not a fan of any other pokemon... The game was great I just was interested in many. But now with the new evolutions, like for roselia, the game would be better.

Anyways, most over-uses = Torchic/Mudkip. I know it's hard not to use them but : P

Edit: I take that back, there were some good pokemon, I remember loving salamance

[Azulart]

General seeing I think: Swampert, Salamence, Metagross and Latios/Latias
were most overused in the game.

For me personal it was Sceptile and Slaking though
Loveing the base stats of slaking. and Hyper Beam being an physical move back in R/S/Y was the bomb in combination with Truant
As for sceptile, I adored him with Leaf blade and Thunder punch being special moves.

[mephistopheles.]

everyone had a swampert.

[Papousse]

Yeah, I'm so original with my Masquerain and my Sharpedo !
Well that's not a difficult question. Salamence is pretty used and strong. Also Metagross, but rare.
I'll say Flygon. Trapinch is so easy to catch and everybody has a Flygon now...

[Zigh]

Most likely Swampert. Water/Ground combo makes it a beast with only one weakness, and STAB's with ground just make it more of a deadly force.

[Shymain]

I think it was the starter that you got, everyone had a starter XD

[wilfredojr1]

Agron, Flygon and Salamance perhaps

[TheRioluKid]

From 3rd Gen... Salamence is my first thought. I haven't played a Gen III game in a while, but even in Platinum, every time I download Wi-Fi data at the Battle Tower, at least one trainer uses one. I can see why people would want them, because they ARE very strong... I'll admit, if Ralts is in the game, I do try to get one because Gardevoir's learnable moves are quite versatile. And Treecko was always my favorite starter (From Gen III), even if he had some gym type disadvantages, he always was and still is my favorite. My first Level 100 was a Sceptile, though at one time I had like a Level 99 Venusaur in Leafgreen.

[Rebel562]

Poochyena/Mightyena. Can never seem to get away from it and its freaking Intimidate when I play Emerald.

[AhTreyYou]

Kyogre introducing perma-rain and Groudon introducing perma-sunlight

[AcePeter]

Zigzagoon, lamers do not want to catch Water-type Pokemon to use Surf nowadays.

[Champion Cynthia108]

Well, to be honest, I use Swampert a little TOO much.

Other than that, Flygon. My gosh I see that thing everywhere >.>

[amittal12]

Among the Pokemon that I use,I think that Gardevoir and Aggron are very common.Swellow is used many times by early game trainers.

And yeah those Rayquaza,Salamence and Flygon.

[asdfDAN]

The starters, Flygon, Salamence, Rayquaza, and an HM slave (probably Zigzagoon).

[Bulba the Great!]

I recall Gardevoir and Salamence being spammed a lot, as well as Milotic. I wasn't huge on the competitive side of things, though.

[Doux]

Flygon.
It's everywhere.

[Agonist]

Swampert, Salamence, Flygon, Metagross, and Milotic.

[Mystical Jackal]

Novice trainers use most these: Swellow, Pelliper, Crobat, Gorebyss/Huntail, Golem, Aggron, Linoone, Raichu, Breloom, Sableye, Slaking, Skarmory, Ninetales, Glalie, Blaziken, Sceptile, Flygon, Zangoose

Experienced players use most these: Salamence, Metagross, Milotic, Walrein, Gyarados, Alakazam, Dusclops, Eeveelution, Tyranitar

***Note: I didn't consider legendaries in spite of some are over used.