Sponsored can identify paid links and ugc can identify user-generated links. Consider nofollow when other values do not apply and you do not want to endorse the association. Values can also be combined.
Google announced the ranking-hint change in 2019; nofollow became a crawling and indexing hint in March 2020. Do not assume other search engines implement the same behavior.
Provide internal navigation links for their intended purpose. If content access or indexing must be restricted, choose suitable access controls or noindex separately. Do not assume nofollow precisely redistributes internal ranking value.