We all know that the Elite Four is the final challenge of the main story of Pokémon games (although, I don't think that applies to BW1 the first time through the E4) and usually your first time through any game you pick up different Pokémon here and there, maybe switching one or two Pokémon that aren't doing well in any battles and then your team gets tested by the Elite Four. Whether or not your team does well is really up to you.

Second time through any game, you know what's ahead and maybe you decide to challenge yourself or have a bit more fun. So my question is what teams have you used against the Elite Four in any game that worked well, failed miserable, or barely got by? Also, what teams would you want to use against a specific Elite Four to see if it adds challenge or makes things more enjoyable?

I remember I was able to go through the Elite Four in Blue Version using my Venusaur, Jolteon, and I want to say a flying or water type, but I can't remember exactly.

From Platinum onwards, I defeated the Elite Four using the normal team I built up as I progressed in the region. But I remember special cases against the Elite Four in 3 games:
-Fire Red; the hardest one I have ever challenged. It took me a lot of retries and I finally defeated them using the three legendary birds and Venasaur.
-Emerald; I remember defeating them with the Lv.70 Rayquaza and Lv.70 Blaziken. I didn't have anything else at that time.
-Diamond: Again, I was still a beginner, who used Dialga and Infernape only.

I vividly remember a few of my times facing the Elite 4.
-Blue: I remember using my Clefable and Charizard a lot for these battles; mostly Clefable because it was pretty overleveled. Overall, my Clefable made this Elite 4 challenge easier than what it was supposed to be.
-Yellow: I definitely used Pikachu a lot along with Articuno. This time, the Elite 4 was harder for me. My Pokemon were underleveled, which led me to losing against Lance a lot.
-Gold: I don't know why, but I had so much trouble against this Elite 4. I used Meganium and Lapras (sometimes Kadabra) to take on this Elite 4. The biggest problem I had was facing Karen, since I didn't have a solid way to counter her team. It took me around....4 years to beat this Elite 4. <: D
-Crystal: I had an easier time with the Elite 4 in Crystal Version, mostly because I used a Jynx (which is actually an excellent Pokemon to use against the Elite 4), Typhlosion, and Suicune. The Johto Elite 4 was so much easier when I used the right Pokemon to counter their teams.
-Sapphire: For some reason, I level grinded a lot in Sapphire version. I only used my Swampert and Gardevoir to take on the Elite 4, but they both were around level 74 when I first took on the Elite 4 and Champion. If I had a lower-leveled team, the Hoenn Elite 4 might've been more of a challenge, but it was quite easy my first time playing through.
-Emerald: I didn't level grind as much in Emerald. I also didn't use the level 70 Rayquaza I caught because I wanted a challenge. However, I again had an easy time with the Hoenn Elite 4....until I got to Drake. Drake nearly wrecked all of my team because only one of my Pokemon knew Ice Beam. Besides Drake, I felt the Hoenn Elite 4 was somewhat easy.
-Pearl: I used 3 Pokemon in my Sinnoh Elite 4 challenge: Empoleon, Roserade, and Mismagius. I felt the Sinnoh Elite 4 was tough because of the sudden level jump from the last gym. (I think it was level 49 to level 57 beginning the Elite 4 to level 66 at the Champion >_>) I also grinded a little in Pear version, but even with the extra levels, my Pokemon were only level 56-58 by the time they fought the Champion. I wouldn't say the Elite 4 was the biggest problem, it was just Cynthia's level 66 Garchomp. Overall, the Sinnoh Elite 4 was a challenge, but it wasn't too difficult of one...until the Champion battle

One thing I like to do is look online, and now through Pokédex 3D, and choose my favorites that appear in that region and form a team of 6. Sometimes 5, for HM Slave room or legendary room.
Diamond- My first game. All I used for attack was an Infernape, and 5 dummy Pokémon. (And you're lucky you had Dialga, Spirit! Me being a beginner, I thought Dialga was an evil Galactic slave, so I killed it in 1 Focus Blast.)
Platinum- I was more serious. Torterra, Rapidash, Noctowl, Weavile, Giratina, and Quagsire.
HeartGold- My Pokémon had partners in this one, but I only used 5. Feraligatr and Gyarados, Kenya and Ampharos, Arcanine and Ho-Oh. (Ho-Oh was short lived, barely even made it use an attack)
Black- This was some of my best work yet. Samurott, Stoutland, Ferrothorn, Darmanitan, Zebstrika, and Unfezant. I traded out Stoutland for Reshiram when I fought N.
I would post my Black 2 team, but I don't know if that would be considered spoilers or not, so I'll just wait, but say that I picked Smugleaf.

I might as well post what I did in Platinum, HeartGold and White.

In Platinum, my team consisted of Infernape, Empoleon, Torterra, Luxray, Staraptor and Giratina.

In HeartGold, my team had no legendary and no starter. It was Machamp, Electabuzz, Crobat, Vaporeon, Scizor and Tangrowth.

In White, my team had no legendary, since I started preferring having a challenge. It consisted of Emboar, Simisage, Seismitoad, Cofagrigus, Galvantula and Haxorus.

I used a Bibarel on my team in Platinum once, it seemed to work pretty well.

In Pokémon Yellow I decided to use Red's team from HG/SS, which turned out to be pretty fun. They're all under level 50, 4 of them still in their mid-30s, so it turned out to be a very tough challenge. Felt good, man.

I also finished off the Elite Four in Emerald with a Blaziken, a Wailmer with ONLY water moves and an underlevelled Altaria. Of the three of them the only one with a decent moveset was Altaria, but it was still pretty bad because of the weird physical/special split before Gen IV.

I remember playing Pokemon Gold years and years ago, and my team prior to challenged the Elite Four was Meganium, Magenton, Fearow, Donphan, Tentacruel, and Kadabra. They were all in the mid to high 30s. The team itself was well balanced in my opinion, but after the first two of the Elite Four (Will and Koga) the rest of the challenge was almost impossible for me. It took me 3 or 4 tries before I even reached Lance. By the time I did reach Lance though, my team had gotten up to the 40s so defeating him was managable.