Item concept: Champion weapon upgrades
Take the weapon your champion is using, and upgrade it to improve the champion. If they arent using a weapon, think something up. This would not take an item slot, instead appearing on the buff bar (like GP ult upgrades)
Examples
Lamp post: 1200 gold for one of the following
Lamp: basic attacks deal bonus true damage over time equal to 10% the damage dealt by the auto (post resistances) and reveal the target for 1.5 seconds.
Defensive stance: Blocking basic attacks with Counter Strike reduces the cooldown by 1 second, stacking up to 5 times per cast.
Real weapon: Damage ignores 20% their armor and magic resist
goop: 1200 gold for one of the following
Cell Walls: take 10% less damage while your passive is up
Acidity: Damaging enemy champions causes them to lose 5 armor and magic resist for 5 seconds, stacking 5 times.
Mitosis: Restore 2.5% your missing health when you take damage (4 second cooldown)
BANANA STAFF: 1200 gold for one of the following
Delicious Potassium: Basic attacks may target allied champions to reduce the duration of any CC on them by 0.5 seconds
Unexpected Fruits: Extend the range of astral infusion to 1000
Starry night: Starcall can now be cast as a target spell
Hextech Gauntlets: 1200 gold for one of the following
Chrome: Mana Barrier now shields based off of Maximum mana instead of current
Titanium: Basic attacks reduce the cooldown of Rocket Grab by 1 second
Steel: Increases armor and magic resist by 15%
Contaminated Crossbow: 1200 gold for one of the following
Cheese: Killing a unit restores 10/15/20/25 health. This is Tripled versus champions.
Sneaky: Kills and assists cause twitch to reset the cooldown of Ambush.
From the sewers: While in a bush, Ambush has no delay.
Chronoexplosives: 1200 for one of the following
Chronoblast: Time bomb stuns on detonation, rather than double bombs.
Time Freeze: Time warp now ignores diminishing returns (an ACTUAL 99% slow).
Longevity: Chronoshift now lasts 10 seconds, and rewind reduces its cooldown by 1 second.