Thanks for doing this!
A quest that always sticks on my memory is Flight of the Wintergarde Defender in WotLK.
Makes you feel like a real hero swooping down to rescue npcs from the scourge battlefield.
My preference is the Heart of the Aspects. I already have or don’t care about the others. Pass me by for another winner if it isn’t available. 
Wrath had a lot of well written quests imo - cata was such a bad experience for me i couldn’t get into the as much as the other expansions 
So hard to choose!
Favorite general interactions: The faerie dragon circle in tirisfal or the armored critters in mulgore maybe. Also the whirlpool (post cataclysm) in darkshore.
Favorite questlines: Fiona’s caravan has already been mentioned so I’m adding the Harrison jones uldum quests and the whole rogue class hall from legion.
Favorite randomness: That one time pirates day glitched out and everyone got stuck in pirate clothes while running around doing brewfest.
But really, there are SO MANY interactions I love that I can’t even think of just one.
As for the prizes, 1-2-3.
The Halls of Reflection. It was a big lore endpoint before Icecrown Citadel, and gave us not a traditional boss encounter, but rather escape from Arthas.
Yesssss! lol
First boss fight was glorious. First time needing to actually think about mechanics in a dungeon to go over smooth. Also, everyone needing the damn shield that came outta there lol
Last day to get entries in
I have all these items but I want to join in anyway for the funsies.
My favourite mechanic / encounter is the gossip in Court of Stars. Something as simple as calling out whatever the gossips are making a list can take forever if you have players too stubborn to play along. Sometimes people don’t even read the quest requirement and rage why the encounter is so hard.
I really want more encounters like it in the game. More like an intelligence and cooperation check than a DPS check.
Prob the valentines event this year, due to getting yhr love rocket (and ill ALWAYS call it that bliz!!, lol). Its my main flying mount for a few of my characters now
And Murlock toy. Been eyeing it for a bit but haven’t bitten the bullet yet
Truthbringer shall bring you to light!
Gratz! Still ugly as sin though lol
Little less than 12 hours to enter for 1 of 3 free gifts
One of my all time favorites is Vanilla Onyxia. Iconic encounter that generated a ton of great memes. “Many whelps! Left Side! Handle it!”
I distinctly remember a clear of her lair in which the last of our tanks died right at the end of the fight. At the time I was playing combat rogue, found myself with aggro, popped evasion and rotated the boss away from the raid, evasion tanked the last few % and finished the kill that way. Good times.
Edit: Whoops, either mount would be my preferred choice.
When did they redo Onyxia? Was it Cata? I did the updated version and always had a blast doing clears
For some reason I thought it was but apparently it was patch 3.2.2 during Wrath.
Huh thats weird. Maybe i just cleared it at the end of Wrath. But i could have sworn it was Cata with the Dragon xpac.
My favorite encounter was the whole secret puzzle back in Legion. I did everything without any addon, but I did discussed with secret finders in discord. I had so much fun discussing ideas with secret finders, pulling my hair after being stumped with the chair puzzle note, and numeric codes.
It took me two days to finish the last puzzle in endless chambers. I was proud of myself finishing and helping others with the puzzles. Even now, I still use Lucid Nightmare.
I’m not interested in mounts, but the toy sounds fun, I’ll prefer that one.
Deal! What was the secret puzzle? Im not much for side games honestly so i may have missed that
I think it was part of a reawakening of dragons leading into Cata, like the Ruby Sanctum raid. Maybe?
Also,‘I’m outta likes but this is such a cool thing. I don’t want or need any of the things your graciously giving away, just passing through. 
Ill take the bumps. My sister’s wedding is today so i wont be able to keep this going for some hours
And the more the merrier so ill take the bumps!
Riddle me this: Lucid Nightmare. It’s a dark horse with purple tint mount, it’s very pretty.
Worth it.
My absolute favourite in the entire game is Maximilian in Un Goro Crater, he thinks the dinosaurs are dragons, its hilarious and he is so confused and at the same time he thinks hes a hero.
My choices are 1. And 2.