Is there a way to identify the objects with more than certain lines or sort objects by lines count?

What "objects" and "line count" do you mean?

If this is about Appian design objects, most objects do not have "lines".

You can use AQuAMan to report on "Lines of Code" for SAIL objects (Interfaces and Expressions) and, in addition, correlate the findings with a Complexity score (lines of code is a poor proxy for complexity), code/comments ratio, test case count (for Expressions only):