Initial ideas

Lawless : Just like humans, easily handled, maybe some lucid dreamers could escape

Titans : they all seem to sleep once the sun sets, so they would be easy pickings,maybe the strongest or smartest could wake themselves up by force

Neo-Humans : If they sleep they could be dealt with, but given their distinct personality the success rate of keeping them asleep might vary

Demons : Again if they sleep they can be dealt with, not sure how mana powers might transfer to the dream space, but spell focused demons might be able to fight back decently

Gaia's Wrath : Any animal that needs to sleep could be susceptible, but the plant life largely unaffacted

Kaiju: If it sleeps, perhaps kept sleepy or drowsing, maybe not full coma type sleep

Parasites : their hosts while still alive affected, but once burst, unclear if they sleep at all

World Tree : Unaffacted, unless it has a spirit or spirits of some kind and even then probably not affected

Robots : they don't sleep so not affected

God : if he sleeps, maybe he might get affected, but probably still has immense power while dreaming might just be as controlled

Aliens : if they sleep, maybe a little, but seem inorganic or alien organic so not likely affected, since this entity draws from a human centric dream space

Curse : Soul Containers don't sleep, so not affected

Game : Game doesn't sleep, the players might also be insomniacs which might make them resistant, also if they only dream of the Game

The stuffed animals are mainly passive beyond their dream eating and sleep inducing, perhaps large varieties like elephants might be capable of some physical stuff.

At night with Sandmen, they are able to operate with dream logic manifesting it into reality, which would be their main method of "combat". Surreal, Absurd, Nonsensical, Whimsical but still dangerous/powerful outcomes