Uploading this open source mod from Nexus Mods because it's not on Thunderstore yet.

Developer: TechGuard

Original mod link: https://www.nexusmods.com/valheim/mods/731

This mod lets split 1 item from a stack

• Place 1 item from a picked stack by right-clicking inside your inventory.
• Split half stack by shift + right-clicking on an item.

Broken features with errors

• Drop 1 item on the ground by right clicking outside your inventory.
• Grab a full stack by double left-clicking (merges multiple items in the inventory).

Configuration

"InventoryUseItem" if you set this to anything other than right-mouse-button, you do not need to hold shift to pick up half a stack.

v1.2.3

• Restored place-one / drop-one (1.2.2 merge hook on InventoryGrid.OnLeftDown could prevent the plugin from patching)

v1.2.2

• Fixed right-click place-one sometimes sucking placed items back onto the held stack (double-click merge was firing on rapid right clicks)

v1.2.1

• Verified in-game on Valheim 1.0
• Shift + right click splits a stack in its slot (no pickup); uses MoveItemToThis so it is not flagged as a cheated item
• Double left click merges matching stacks into the clicked slot and does not pick them up
• Place one / drop one keep the remaining stack on the cursor

v1.2.0

• Updated for Valheim 1.0 (Unity 6)
• Build now references Unity assemblies from valheim_Data/Managed
• BepInEx dependency updated to denikson-BepInExPack_Valheim-5.4.2350
• Keep the dragged stack on the cursor while right-clicking (ZInput.GetMouseButton in UpdateItemDrag)
• Place 1 item from a held stack with right click; remaining items stay on the cursor
• Right click outside the inventory grids drops 1 item from the held stack

v1.1.1

• Updated to work with Mistlands

v1.1.0

• Added config entry to override inventory "use" input (defaults to right-click)
• Shift + Right-click will pick up half of the stack
• Double Left-click will grab a full stack of the selected item