Gakido is Nagato's rinnegan technique (some of the people you listed there don't even have a rinnegan) and he's the only one who can use it.
As for superior absorption ninjutsu it would be either Kaguya or Momoshiki because Kaguya's sharingan powers allowed her to absorb people just like how Momoshiki's rinnegan was able to absorb Kinishiki but in the shape of a fruit.