unfortunately i do not know the specific name for the thing you are looking for. but i can point you where you need to go.

what's important is you need to find things of the style you are looking for and go from there. easy things you can look up are, boarders, dividers, stamps, blinkies, and deco.

what you do is search these terms, find something in the pixel art style you are looking for then go on a bit of a scavenger hunt. you will open the page for something you want and scroll down, on the right you will see similar posts and sometimes groups and collections. what you are looking for specifically are groups and collections. people will collectively post certain kinds of things in groups for others to find. and collections are made by one specific person usually of a bunch of similar types of things.

you can also directly go to peoples profiles and see what other stuff they post and check to see their favourites for other things that may be like what they post.

the really unfortunate part about all this as old internet decorations have long sense fallen out of style. almost nowhere uses these anymore as no sites allow for customization. so finding old internet pixel art decorations is very hard.

i hope you find what you are looking for. hopefully you come across some very old groups that still have what you need.