Wow, I like these submissions.
Thick Fat Togekiss : That's huge ! He is not only a premier CharX counter, but a complete Charizard counter :
Togekiss
Leftovers
Ability: Thick Fat
EV: 252 HP / 152 Def / 104 SpD
Bold nature
- Roost / Wish
- Heal Bell / Protect
- Dazzling Gleam / Air Slash
- Thunder Wave
+2 252+ Atk Tough Claws Mega Charizard X Flare Blitz vs. 252 HP / 152+ Def Thick Fat Togekiss: 234-276 (62.5 - 73.7%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery
252 SpA Mega Charizard Y Fire Blast vs. 252 HP / 104 SpD Thick Fat Togekiss in Sun: 127-150 (33.9 - 40.1%) -- guaranteed 3HKO after Stealth Rock and Leftovers recovery
Honestly, the only move that really matters here (against Charizard) is Thunder Wave. Togekiss struggles to deal damages to Charizard, but a T-Waved Zard is a dead Zard. Then, you can run whatever utility you want. Aside from Charizard, you are better against Victini, Volcarona and Entei... And he counters the whole classic coverage alongside Dragon (Fighting / Fire / Ground --> Classic MegaChomp is walled). That's not much, in fact, because a lot of things with Fire-moves can still annoy Togekiss. Banded Talonflamme 2KOes with BB, SpDef Heatran didn't do any relevant damages.
And about the Ice neutrality, it's great against Mamoswine (Icicle Crash does not 2KOes... but you only 3KOes), Kyurem (rare) and Weavile. But I guess it's nice.
But still, the ability to be a nearly surefire Charizard counter is amazing. And he does not lose that much : offensive set likes the opportunities to come-in granted by Thick Fat too.
Steel / Dragon Druddigon
This is my least favorite. I mean, Dragon / Steel is a good typing, and he would have Sheer Force Iron Head I believe but... He still has only decent bulk (77/90/90 is not impressive). I don't know what he can do. A bulky set (with Glare / Dragon Tail) ? He direly lack any kind of recovery (even a Drain Punch-like would be decent) and Garchomp has a much better bulk. Remember he is still weak to Fire / Ground / Fighting. Because of it's Dragon typing, he can't really check Fairies (he is still slower than M-Mawile for fuck'sake). When you look at the most impressive threats of the metagame, Druddigon just does nothing. M-Pinsir stomps him at +2, Char-X has the only problem of taking a huge chunk of recoil damages through Rough Skin but it could be worse, M-Gyarados has Earthquake and normal Gyarados may sub on him (hard though)... What is its niche ? He can't take on anything in the metagame, except Scizor, Venusaur (bar Leech Seed. Considering he can't do anything in return, that's big), mayyyyybe Clefable (I doubt he can stomach Sylveon), Ferrothorn bar Leech Seed, Zapdos and Rotom (who will burn him).
I just have no clue on why should I use him. A Fairy-slayer Dragon ? I doubt it.7
Prankster Gourgheist
Wow, that's gonna be a thing. Like others said, a Disable / Sub / WoW / Leech Seed set is just so freakin' annoying. He is really bulky so you can't really hope to kill before he starts burning you. You will want something with Infiltrator to deal with this, which means Crobat (who will be burnt, yay) or Noivern. Else, rely on something like Celebi to absorb the WoW but it's just so annoying. Honestly, even though it seems really a great and interesting buff, I don't want it. Just because he would so (yeah I'm repeating myself) annoying. Bulk, priority burn, priority sub... What else ?
You could also run Choice Spec Exploud, hah.
But I will definitely second other people here. I just don't see how to deal with him once he switch in on one of your Pokemon, apart of some obscure sets (Noivern being the most common. Yeah.)