1 · Mount kit — chest, helmet, handlebar: 80% of every adventure edit ever made. Check price on Amazon →
2 · Batteries — buy two, rotate three. Cold and cold weather are battery thieves. Check price on Amazon →
3 · ND filters — motion blur is the difference between footage and film. Check price on Amazon →
4 · Memory — U3/V30 256 GB; 4K120 eats slower cards alive. Check price on Amazon →
5 · Waterproof case & float — surf, dive, kayak insurance. Check price on Amazon →
6 · The all-in-one bundle — camera-adjacent gift boxes that cover mounts, case and card in one order. Check price on Amazon →
The two we don't recommend yet
Sub-$100 "4K" cameras and no-name gimbals — we say so instead of finding links. A cheap accessory from a known brand beats a cheap everything from an unknown one.