If you're looking to add polarizing or ND filters to the GoPro HERO7 cameras, the HERO6 Black, HERO5 Black, or HERO (2018), PolarPro has a 3-pack kit of snap-on filters specifically for these camera models. Here's my hands-on review.
GoPro Filters and Lenses
Reviews, tips and tricks related to GoPro filters and lenses.
If you're looking to add a neutral density, polarizer, or macro filter to your GoPro HERO4 Black or Silver, PolarPro has a 3-pack that's worth a look.
Adding a Polarizer Filter or Neutral Density Filter to a GoPro HERO3+ Black, HERO4 Silver, and HERO4 Black
Review of the Fotodiox Pro WonderPana Go H3+ Standard Kit for installing a polarizer filter or neutral density filter to the GoPro HERO3+, HERO4 Silver, and HERO4 Black.
A polarizing filter on a GoPro HERO3 can reduce glare and saturate colors. They work especially well above water, with snow, or with bright sunshine.