A CB set can easily use both Wood Hammer and Horn Leech. CB Wood Hammer hits harder than a banded v-create from victini or a +1 hyper voice from a modest mega gardevoir on the special side. its really no joke and you're unlikely to be clicking anything else because it hits harder resisted than a neutral Superpower, for instance. Horn Leech also hits very hard, turning into the equivalent of a 110 BP healing move thanks to grassy terrain boost, and then that gets CB boosted also. I would use Wood Hammer, Horn Leech, Superpower, and Zen Headbutt. Megahorn might seem logical to hit grass types really hard, but a non-double grass resist from a grass typing is still going to turn into a 2hko in many cases
Tangrowth is basically the benchmark for avoiding a 2hko from wood hammer when it comes to defenses with a single grass resist rather than a double:
252+ Atk Choice Band Tapu Bulu Wood Hammer vs. 252 HP / 252 Def Tangrowth in Grassy Terrain: 164-193 (45.5 - 53.6%) -- 93.4% chance to 2HKO after Stealth Rock and Grassy Terrain recovery
Other single resists get swept away. Then the most common 4x weaknesses will be covered by superpower, zen headbutt, or none of tapu bulu's coverage at all:
252+ Atk Choice Band Tapu Bulu Zen Headbutt vs. 248 HP / 252+ Def Mega Venusaur: 180-212 (49.5 - 58.4%) -- 64.5% chance to 2HKO after Grassy Terrain recovery
Birds are scary i guess, but talonflame would get ohkod switching into rocks and wood hammer, and hasty tornadus-t would get ohkod without rocks. I know some of these mons arent available yet at the start of sun + moon but I am thinkin about what might happen in the meta in the future