Hearthpwn

No question the Hunter NAGA on wild!

Honestly, was a big fan of Un'goro meta. Yeah, quest rogue was annoying, but it wasn't terrible back then. But we had all kinds of crazy quest decks, sherazin rogue, taunt warrior, buff paladin, elemental shaman. Elise had us opening packs in our decks, it was just a fun time. Probably most I've ever enjoyed hearthstone.

Knight of Frozen Throne meta back in mid 2017...  all classes (except Hunter) were relevant. 

I think the time I enjoyed the meta the most has got to be some chunks of year of the raven (when I was still playing standard):

During Witchwood I really enjoyed facing cubelock (expecially post nerf, b4 that it was quite OP, but still ok....most of the time) and hadronox druid (unless they highrolled) , yes the Shudderwock infinite combo was horrible to fight but, without going infinite, the card itself was REALLY fun to play/buildaround, even though I never had much success with it in standard, I did enjoy myself. (yes Ik quest rogue has been a thing for some time but I was low rank enough that it wasn't THAT big of a problem)

In Boomsday many toxic bs cards like Mecha'thun or enablers for said degenerate cards/decks were added and druid had 37 different horrifingly toxic decks that's true but they also added stuff like the "control warrior package" with Supercollider, Omega Assembly and Dr. Boom, Mad Genius to make up for it, also that's the timeframe when deathrattle/DKRexxar hunter (my personal favourite deck to play against) actually took off.

Rashtakan is probably the time I enjoyed most of all out of these: they nerfed a lot of the bs decks AND they added a little bit of support for some more fun decks, I could play elemental shaman/mage as great value decks, quest priest and a "slower" version of quest warrior were my favourite "exaust the opponent" kind of decks. Also did I mentioned that I enjoyed facing DKRexxar? I can't quite remember if I ever expressed that feeling on this site.

I really liked it when they released Rise of Shadows.  The game felt very fresh, I would say probably the best expansion that has come straight after a rotation.

More recently, I thought they did an excellent job with Scholomance.

Quote from Dellron >>

Honestly, was a big fan of Un'goro meta. Yeah, quest rogue was annoying, but it wasn't terrible back then. But we had all kinds of crazy quest decks, sherazin rogue, taunt warrior, buff paladin, elemental shaman. Elise had us opening packs in our decks, it was just a fun time. Probably most I've ever enjoyed hearthstone.

 Un'goro was the best ;)

Naxxramas, after the Undertaker nerf I had a lot of fun

Quote from Bengalaas >>

Naxxramas, after the Undertaker nerf I had a lot of fun

Yes, this one wasn't even around long enough to fully stabilize, and was very balanced iirc, maybe with mage struggling.

I think it is between this and Un'goro. The C'thun decks were pretty fun and different when they were introduced as well.

Vanilla (now Classic) was the best meta - all classes were relevant, and the game was generally pretty fun and interactive (tm). Will probably play Classic next season, I didn't want to miss expansion launch meta and may as well go to Legend now. I played the most in GvG though, so that's the meta I had the most fun in. Un'goro and Scholomance (in that order) were the best since. 

Un'Goro

Kobolds & Catacombs prenerf was my favorite. I think it was the highest power level meta we ever had in standard. All of the decks were super busted and many classes had access to the busted cards because they were neutral.

As a F2P player I always liked powerful neutral cards that go into many decks but the comunity always complained about them so Blizzard printed less and less of them lately.

My second favorite is Classic Mode which I can play today. I'm having a lot more fun in Classic than I anticipated.

Whatever Patron Warrior was in. Most fun deck ever. Aside of that Naxx for sure.

Priest’s winrate in Classic is 38%

Ungoro meta as miracle rogue was by far my favorite. 

Unpopular opinion, but for me it was The Grand Tournament! :) 

Un'goro, descedant of dragons probably.

Quote from Shagohod >>

Whatever Patron Warrior was in. Most fun deck ever. Aside of that Naxx for sure.

Please no! Patron was so annoying 

Quote from Bengalaas >>

Naxxramas, after the Undertaker nerf I had a lot of fun

 I liked the og Undertaker. Was the first time I got to legend ;)

Personally I enjoyed GvG the most. I felt like it was when the game really started to open up and things felt a lot more balanced. The GvG midrange paladin is probably my favourite deck of all time. I didn't play for half of 2017 and most of 2018 (was travelling a lot and didn't have the time to dedicate to the game) so I missed those expansions.

If I had to pick my worst it would definitely be classic or outland. Having went back and played classic a few weeks ago - it just shows how broken and unbalanced the game was back then. Priest, Paladin and Shaman none existent in the meta and just an all round bad experience. I really hope they reintroduce naxx and gvg to classic. I think they will eventually as no one plays it anymore.

Ungoro post-nerf was amazing. The ammount of burn mage I played back then hasn't been matched yet by any deck