Thanos visits various universes to comment on them

[Steel Inquisitor]

What does Thanos think of these universe? This is 616 Thanos. He'll just be observing, not impact the plots.

Marvel Cinematic Universe
Buffy/Angel
Blade films
Netflix Marvel
Altered Carbon (Netflix)
Chilling Adventures of Sabrina
90's Marvel Action Hour
Various Spider-man cartoons
Various X-men cartoons
The Witcher (video game and tv show)
Birds of Prey tv show
DCEU
Supernatural
Spawn (HBO)
Spawn (movie)
Fox X-men film 'verse
Firefly
Sarah Connor Chronicles
Game of Thrones
Terminator movies
Watchmen (tv show and movie)
Christopher Reeve Superman films
The Dark Crystal (movie and tv show)

Add more.

Edit: Vampire Diaries CW 'verse (TVD, Originals and Legacies)
The Arrow 'verse

[Shai-Hulud]

Watchmen (tv show and movie)

Thanos builds his own intrinsic field subtractor in order to attain Doctor Manhattan-level powers.