Assumption: You are talking about a results list that does not live on a separate page (full page experience) and I am assuming this is some sort of search or auto complete type of a feature.
What I learned:
In the studies I've done, a magic number for a list is between 5 and 9. If you display less than 5 users don't mind seeing more and after 9 information quickly becomes overwhelming.
Your example:
Short Answer:
Best practice is to display a spinner (animated image) and/or a label "loading results" or something similar to notify a user that the process is still preparing results.
Long Answer:
Showing a skeleton is ONLY going to be helpful if you know you would have to display 100 results and you display 100 skeleton items. If the number of skeleton / placeholder items does not match the number of items in the result - it will raise more questions from the user stand point.
Why did I see 10 and all of a sudden that changes to 3, where did the other 7 go?
If I saw 3 placeholder items and now I see a 100, where did these extra items come from? Did i make a mistake in my search query?
Also, as a side note, if a user is searching for something and they find 2000 results, they most likely wont go through all 2000, unless they ned to do a mass action of some sort. Paginating that list or breaking results into smaller groups is recommended to keep the load times shorter and page weight smaller.