Advanced Shulkerboxes

Advanced Shulkerboxes is a mod that allows players to open Shulker boxes while sneaking so they don't have to place it down/pick it up all the time.

Rift 1.13 version: https://www.curseforge.com/minecraft/mc-mods/advanced-shulkerboxes/files/2608306

This mod lets you open your Shulker Boxes from your inventory.

Just right-click the Shulker Box in your inventory and it opens up.

You can place it down by sneaking.

Trivia
The Rift version is the only time the mod has been for another modloader as the mod as always been for Forge (there is no Liteloader (likely not possible) or Fabric version).