When to use nofollow, sponsored, and UGC
Google still reads the rel values on links. You do not need every outbound URL to be nofollow. You do need the paid and user-generated ones marked so the page matches how the link was created.
sponsored
Use this when money, product, or a barter deal is involved: affiliate links, paid reviews, sponsored placements, and most advertorials. Google asked publishers to use sponsored (or nofollow) for paid links. If you already have a disclosure on the page, still add the attribute on the link.
ugc
Use this on links you did not write: comments, forum posts, guest bios you did not vet as editorial, and other visitor content. It tells crawlers the destination came from a user, not from your own recommendation.
nofollow
Use this when you want a general “do not treat this as an endorsement” signal and the link is not clearly paid or user-generated. Examples: untrusted citations, login or cart URLs, and some official resources you are listing without promoting.
You can combine them
rel="sponsored nofollow" is valid. The homepage tool writes the values you check, in one attribute. New-tab links also receive noopener and noreferrer. Those last two are for the browser, not for ranking.
What not to do
Do not nofollow every external link by default. Editorial citations can stay as normal follow links. Do not mark a paid link as a regular follow link and hope a page-level disclaimer is enough. Do not invent extra rel tokens; stick to the three Google documents.
Set the checkboxes in the generator before you copy a campaign list, then keep the same rule for the whole batch.