About to start Hearts of Stone and Blood and Wine from The Witcher 3. I was wondering is there any expansion/DLC that beats these cause I can't think of any. The ones that come to the top of my head are so far behind these masterpieces. 

Oh man several immediately come to mind

Warcraft 3 - Frozen Throne
StarCraft - Brood War
Cyberpunk 2077 - Phantom Liberty
Destiny - The Taken King
World of Warcraft - Wrath of the Lich King
Elder Scrolls 4 Oblivion - Shivering Isles

Don't know if that's the exact placements I would put them, but they're definitely among the best

I just realized I probably haven't played a ton of expansions, but some of the good ones include:

• Commmand & Conquer: Red Alert 2 - Yuri's Revenge
• Grim Dawn - Ashes of Malmouth and Forgotten Gods (Fangs of Asterkarn falls short of both of them so far, expect for great endgame additions)
• Titan Quest - Immortal Throne

Some Total War games also have some well-reputed expansions, I believe, e.g. Fall of the Samurai for Shogun 2.

Many of the Truck Simulator map expansions are also considered quite good. They're not my favourite kind of a game, but I've had some fun with ETS2, including some nice map expansions.

Do standalone expansions count? Crysis: Warhead was really good for the most part.

I can’t think of a single game expansion that I’ve really enjoyed. Usually it just feels like extra fluff onto an alright great game.

That said, I do remember enjoying the BotW DLC packs released back in 2017, though I do not remember what was even new. (Perhaps I just liked playing BotW?)

I forgot about this type of expansion. Like War of the Chosen for Xcom 2 or Dragons Dogma 2 which is current. I'm not sure if they count, they are more like remasters with side content thrown in. It probably is cause you loved BOTW, I feel the same way about Xcom 2, not knowing what exactly was expanded over the base game asides from the obvious slight content changes. 

Xenoblade Torna. Your poll should have an Other option btw