Inventory Plus
Inventory Plus brings restocking, sorting, slot locking, and tool switching into one client-side mod.
Sort
The Sort button on a chest gathers scattered items into full stacks, in category order. Right-click it to sort by quantity, ID, or rarity instead.
Move Matching
One click moves every item the chest already holds out of your inventory and into the chest. Everything else stays where it is.
Restock
A diamond pickaxe breaks while digging, and the iron pickaxe from the inventory takes its place in the same slot.
Restock for blocks
The stack of deepslate in hand runs out mid-tower, and the next stack from the inventory refills the slot.
Auto Tool Switch
Start mining stone with a sword in hand and the pickaxe comes in. Stop, and the sword comes back a moment later. It's off by default.
Lock groups
Locked slots stay where they are when you sort, and the loose stacks gather at the top around them.
Item tooltips
Tooltips add a line under each enchantment, durability, tool stats, and how the item compares with the one in your hand.
Settings: Reach
The settings menu on the Reach tab, where you choose which lock groups each way of moving items can take from and put into.
Column Cycler
Press Up to bring the next item from the column above the selected slot into your hotbar. Here it cycles stone bricks, oak planks, bricks, and glass. It's off by default.
Hotbar Cycler
Press ] to swap your whole hotbar with the next row of your inventory. Here the everyday hotbar trades places with a redstone row and a builder's row. It's off by default.
Made in Blender
I made the thumbnail in Blender.