How to get items on one square platforms?

Solution 1:

The following abilities let you reach these:

• Artful Dodger grants Knightly Leap at level 2 which lets you jump like a chess knight
• Psionics grants Psychokinetic Shove at level 2 which lets you push the item off that platform
• Mathemagic grants Froda's Jump Discontinuity at level 1 which randomly teleports you a short distance, so it might take a while to get there. On level 5 you get Xeuclid's Translation a more expensive but non-random teleport.
• Ley Lines grants Invisible Geometries at level 5. It lets you move in cardinal directions, but costs a ton of mana. This skill is especially useful in wizard builds.

Solution 2:

Use a concussion bomb.

You make it with the tinker kit, the recipe is something like:

1 × Gunpowder → Makeshift Bomb(s)
Does not require any Tinker skill (requires level 0).
Higher skill creates more bombs, up to a max of 6

Then

2 × Makeshift Bomb → Concussion Bomb(s)
Requires Tinkerer Skill level 1 or higher.
Higher skill creates more bombs, up to a max of 3