Advanced Creative Tab

Commands (Brigadier suggestion for version > 1.15)

/act [help] : show all commands

/act edit : Edit your inhand item

/act head [name=you] : Give a head by a name

/act rename <name> : Rename your inhand item

/act rfw : Get a random (legit seems) fireworks

/act enchant [enchant] [level] : Enchant the inhand item (require > ACT 1.13.2)

/act format [format] : Get formatting help (require > ACT 1.13.2)

/act info : Get mod information (require > ACT 1.16)

/gm [mode] = /gamemode [mode]

/gms = /gamemode survival

/gmc = /gamemode creative

/gma = /gamemode adventure (require > ACT 1.13.2)

/gmsp = /gamemode spectator (require > ACT 1.13.2)

Menus

Mod Menu, can be get with [N] (can be changed) or in mods list with the config button

Left Click : Open in the giver

Right Click : Give in your inventory (you must be in creative)

Shift Left Click : Copy

Shift Right Click : Delete

Giver menu, can be get with [Y] (can be changed) or in the menu by clicking on an item

Give : Give (you must be in creative)

Copy : Copy give information in you clipboard

Item Editor : open it in the item editor

Delete (if you are from the menu) : Delete this from config

Save (if you're not from the menu) : Save this in your config

Cancel (if you are from the menu) : Don't save edit

Done (if you are from the menu) : Save edit

Done (if you're not from the menu) : Close the menu

Item editor, can be get with [H] (can be changed) or in the giver

Here is a list of the changes made by the buttons : (type change Item's type …)

You can add & to use color formatting in name and description

Meta menu

You can also edit there item with new menus : 

Leather Armor -> Change color

Color picker (Click at top to set the default color)

Advanced color picker

Head -> Change Skin / UUID / Link and download skins

You can build a head with a name [Load by name] or with UUID/Link [Load by link], [Download skin] will only work if there is a link

Command Block (+Command Block Minecart) -> Change command / custom name (if the item hasn't already a name) and if the command need redstone to be run

Command Block editor (type = Normal/Repeating/Chain/Minecart)

Command output :

Fireworks -> Change flight duration and explosions

Fireworks editor

Firework star -> Change explosion

Explosion editor (See Minecraft Wiki for more information)

Potion (+Tipped Arrow) -> Change effects, type and color

Duration : in tick (1/20s)

Amplifier : level – 1, for example Speed with an amplifier of 1 is Speed II

Ambient : whether or not this is an effect provided by a beacon and therefore should be less intrusive on the screen. This tag is optional and defaults to 0. Due to a bug, it has no effect on splash potions.

Show Particules : whether or not this effect produces particles. This tag is optional and defaults to 1. Due to a bug, it has no effect on splash potions.

(Minecraft wiki)

Enchanted Book -> Change book enchantments

Egg -> Change what mob can spawn

ToolTip information

By Shifting when you looking at an item in you inventory you can get some information :

Combat : Creative tab

Color : Armor/Potion color

Durability (With colors) : How many time you can use your tool/armor

RepairCost : how much you need to repair/rename/enchant-it in a anvil

Tags(Count) : List of NBT tag of this item

[Y] (can be changed) : Open this item in the giver

[N] (can be changed) : Save this in your ACT Menu

Advanced Creative Tab

This tab contain every non-findable items in creative

1.x versions depleted, please use for an 1.8 version ATEHUD instead (1.8.9)