Back in BW, before the format changed, if you clicked on a move / item / ability on that subpage there was a short paragraph detailing its viability (or lack thereof). Could we do something like that again? Stuff I've got in mind:
Flyinium Z
Usually used to negate the drawbacks of the more powerful Flying type moves, notably Hurricane's low accuracy, Brave Bird's recoil, and the charge turns of Fly and Bounce. A fairly common item in OU, with notable users including Landorus-T, Tornadus-T and Gyarados.
Stone Edge
Despite its shaky accuracy, Stone Edge is still the go to STAB for most physically inclined Rock types. The power difference compared to Rock Slide means it is still the preferred option most of the time. It also commonly sees use as a coverage move on Ground, Fighting and Grass types, to hit the Bug and Flying types that resist their STABs for super effective damage.
Mewtwonite X
Mega Mewtwo X is laregly outclassed as a physically inclined Psychic type by Dusk Mane Necrozma and Ultra Necrozma, which have better typing, more useful abilities and don't fill your mega slot. As a Fighting type, it is often eclipsed by Marshadow and Mega Lucario; the former has Spectral Thief and perfect neutral coverage with its STABs, the latter can also check Xerneas. There's little reason to use Mega Mewtwo X.
Guts
Guts is a fantastic ability for any physical attacker, as it lets them bypass the burns which would normally shut them down, and actually use them to power up. In fact, many Pokemon with Guts run the item Flame Orb so they can always get the boost.