custom-items.yml

About all configuration in custom-items.yml, this also applies on the custom GUI configuration.

Configuration

items:
  closeMenu:
    material: BARRIER
    amount: 1
    name: '&cClose'
    slot: 49
    glowing: false
    CustomModelData: 0
    hide_attributes: false
    usePermission: false
    permission: 'none'
    lore:
      - '&7Click me to close'
    left-click-commands:
      - '[CLOSE]'
    right-click-commands:
      - '[CLOSE]'

Options	Description
material:	define the item's material.
amount:	items amount.
slot:	select specified slot for the items.
glowing:	add glowing effect on the items.
CustomModelData:	set custom model data for items.
hide_attributes:	hide item's attributes.
usePermission:	make the items only player that has specified permission that can see the items.
permission:	permission for the item permission, only applies if usePermission is enabled.
lore:	items lore
left-click-commands:	various tasks when players click the items with left click.
right-click-commands:	various tasks when players click the items with right click.

PlaceholderAPI and Color Codes are supported in name, lore, and click commands.

Custom Head Textures

Basically with this plugin, you can use custom head textures as the item. All you need to do is changing the material, you can get player's head, and texture head, you can the textures on minecraft-heads.com, see the example below.

items:
  closeMenu:
    material: head;<playername/textures>

Get minecraft custom head on minecraft-heads.com

Inventory Slots Item

Player's Inventory Slot

Also with this plugin you can get any items that are on player's inventory. All you need to do is change the material, for example If you want to get hotbar number 9 you need to put slots;8 as the material name, and the slots start on 0, it's just how programming works, see the example below.

items:
  closeMenu:
    material: slots;<slot number>

Slots start on 0, so If you want to get hotbar number 1 you need to put 0 on the material.