Qualify paid and user-created links correctly
Search engines use link relationship values to understand why a link exists. Choose sponsored for compensated placements, ugc for user-created links, and nofollow when you prefer not to associate with a destination and a more specific value does not apply.
Keep natural editorial links simple
A normal, trusted editorial reference generally needs no special rel value. Do not add nofollow automatically to every external link, because useful web citations help readers verify information.
Security values are different
noopener and noreferrer relate to browser behavior and referrer information. They are not substitutes for sponsored or ugc, which describe the reason for a link.