As I understand it, "any" is used instead of "some" when forming a question or indicating a negative

as in
do you have any?
I have some
I don't have any

"Do you have some" is technically bad grammar. As is "I don't have some".

The question "did you find anything" is more open ended - the answer could be "I found something" or "I didn't find anything".

"Did you find everything" is referring to a known quantity - the "everything", more clearly defined than "something" which is more vague.

I had to teach this class in TEFL. It is a head wreaker.