Jennifer Lyons GPI are SUPER STRICT on the FTC rules. You cannot offer anything more than a $25 gift card, and cannot ask for a 5* review, and cannot only target high NPS etc. I know of someone who had big trouble because of this and all their reviews for their campaign were removed.
G2 follow the same principles but not as strict. For G2 you can add an additional incentive on top of the $25 gift card e.g. an additional gift card, or swag etc.
For our reviews I target the entire database for the products we want reviewed. I also ask our customer advocates. And we ask people after a positive CSAT to leave a review. We do some in-product asks as well.
Hope that helps.
