Shoe Spikes

Run into a wall in midair and you catch on it, sliding down slowly instead of dropping. From there you can jump off, catch the opposite face, and work your way up a vertical shaft under your own power. Holding down speeds the slide back up, which is how you get down the shaft again afterward.

Climbing Claws do the same job and turn up in surface chests, while these come out of gold chests underground and jungle chests. Wearing both is not redundant. Together you stop dead against a wall rather than sliding, which is what you want when you need to hold a position and shoot something. Merge them into Tiger Climbing Gear as soon as you have a Tinkerer's Workshop and take the accessory slot back.

Shimmer converts one into the other, so a world that only gave you the wrong half is no longer a dead end.