Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
I propose that Tr’s 43 (Overheat) and 71 (Leaf Storm) should be moved from useless items to usually useless items. As when flung they give the move a 130 base power which is the same as Iron Ball but you don’t lose speed.
While we're at it, the evolution items added in Gen 8 (Polteageist pots, Galarica Wreath, not the Galarica Cuff from some reason) need to be moved to Useless Items, while Binding Band and Big Root should go in Items (I'd argue they're more useful than Absorb Bulb and Shell Bell, and they're definitely more useful than everything else in Usually Useless Items [besides maybe Ring Target, I've seen that used on Trick lures to support things like Regieleki, which is more than I can say for Band and Root])
Fling is a fundamentally horrible move in almost every format, regardless of what item it is, because it's one-use. Maybe this could work in 1v1 where games only last a couple turns, but that's all, and a 1v1 player would need to say it's remotely viable there.
Big Root should definitely be used, though Shell Bell has occasionally also been used in singles. Never heard of Binding Band, Absorb Buble, or Ring Target being used by viable teams.
Fling is a fundamentally horrible move in almost every format, regardless of what item it is, because it's one-use. Maybe this could work in 1v1 where games only last a couple turns, but that's all, and a 1v1 player would need to say it's remotely viable there.
It’s on a sample team for 2v2 https://pokepast.es/fa8b9ffbb940c39b and they could also be used in Vgc as well as the aforementioned 1v1. Even if it is a slight niche it’s still a niche so I think they should should move out of useless items as they do indeed have a use.