How can I find contribution pages or membership pages where Profiles are used?
If you have access to your db then you can look for the field in the civicrm_uf_field and look for the uf_group_id, then look in the civicrm_uf_group table to see which Profile it is used for, and then look in the civicrm_uf_join table to see where those uf_group_id are used. EG you may see that uf_group_id xx is used for civicrm_contribution_page that has entity_id yy