-start is a pagegen argument, but it is also implemented in
- checkimages.py
- misspelling.py
- pagefromfile.py
- redirect.py
- solve_disambiguation.py
- states_redirect.py
misspelling.py, redirect.py and solve_disambiguation.py have their own -start because they support dumps, which are not supported by pagegen: T85334
interwiki.py also has -start_id