Chlorophyte gear currently stands as one of the most useless tiers of equipment in the game; it's just so much easier to skip the armour/weapons and create Shroomite/Sprectre bars with whatever Chlorophyte you managed to mine before defeating Plantera.
Really wish there was more armour sets similar to the Crystal Assassin armour/more dual class armour sets in general so that non-class based playthroughs were more viable. You know, something that defends for a moderate amount and provides stat boosts, but not to the extent of specialised builds of their tier.
If I was going to name an item in this game that's literally useless, it'd probably be the hook. The normal Grappling Hook is so much harder to get than gem hooks due to the hook's rarity, and yet it has the least range of any grapple save for the Web Slinger, tied with the amethyst one.
At what point would you say that the hardmode ore swords overtake the Breaker Blade in terms of effectiveness? They do more damage starting from Palladium, but the damage boost against enemies above 90% health for the Breaker Blade is hard to ignore.