Quite a few things fit. Stars can be images, people, or animals, including Starfish! (and If we use the term loosely even plants - star rose, star daisy e.g. the Shasta Daisy "Ice Star'). I forgot for a moment the "earthstar" fungus and snowflakes - well rather the ice flakes (ice flowers) they leave on windows - they look like stars to me.
Starting with images:- Star decorated dinnerware, even inside saucepans or cookers. Stars on flags, material, paper or on walls/ceilings/windows. Star decorated chairs, furniture, cars/vehicles, ships, books, toys ... anything physical decorated with stars (or look like) basically.
With "people" (or some thing considered a '"star" from the animal (or any) kingdom), any recorded, physical copy of a movie, or recorded media (dvd, YouTube saved to harddisk, ...) that includes someone (or animal, or plant) considered a "star", which covers quite a range depending on one's definition of "star". I'm sure Lassie would be considered one ... and yes there are "Star bugs" and while we are on the topic there are star eggs believed to be laid by butterflies (Nymphalia antiopa).
The definition of "sitting" may reduce this range, but if we consider the television (the most common answer to this riddle) that just means placed somewhere, which can apply to pretty much any physical item. Guess it all depends on your point of view. Just for interest I looked up "star rocks" apparently they exist too - they are a form of data, but it's probably a bit of a stretch including them. So most kingdoms. Did I miss anything?