These are all the actions currently programmed and usable.

Action type	Provider	Description	Options
actionbar_message	JayLib	Sends an action bar message	message String chat message that supports all formatting options.
add_velocity	JayLib	Adds momentum to the player	x Double. y Double. z Double
chat_message	JayLib	Sends the player a chat message	message String chat message that supports all formatting options.
give_custom_head	JayLib	Gives the player a custom head, must be in the head database	custom_head NamespacedId: head id in the heads database. title String The item name. mailbox Boolean(false)
give_item	JayLib	Gives the player an item	item String the item to give the player, same format as mojangs /give. mailbox Bool(false)
play_sound	JayLib	Plays a sound at the players position	sound a String ResourceLocation of the sound to play, volume Float, default 1.0. pitch Float, default 1.0
potion_effect	JayLib	Applies a potion effect on the player.	potion NamespacedId, duration Int(8). amplifier Int(0), ambient Bool(false). visible Bool (true). showicon Bool(true)
server_command	JayLib	Executes a command as the server, can use the variables %username% and %uuid% as placeholders for the player's info	command a String command (without the slash) to execute.
teleport	JayLib	Teleport the player to the provided fixed position	x Double. y Double. z Double yaw Float. pitch Float. world String(default: same world). cause String (default:GAME)
title_message	JayLib	Sends an title or clear title message to the player.	clear Bool(if this is true nothing else can be set). title String message, subtitle String message. fadein Int(10). stay Int(70). fadeout Int(20).
tick_delay	JayLib	A delay function that allows delaying the next actions in the sequence, to preform a sort of animation	delay Int: delay in ticks.
objective_start	ZygardeAdventure	Starts an objective. Only one can be started at a time.	objective String objective id
objective_complete	ZygardeAdventure	Completes an objective moving it into the completed objectives list and setting the active to none.	objective String objective id
objective_switch	ZygardeAdventure	Switches handling off depending on the objective state.	objective String objective id. completed_actions Actions, a list of actions to run if the objective has been completed by the player. active_actions Actions, a list of actions to run if the objective is active for the player. missing_actions Actions, a list of actions to run if the objective is neither completed nor active.
nbt_merge	LimitlessPixelmon	Allows for adding nbt data into the players persistent nbt	tag JSON object
grant_mega_ring	LimitlessPixelmon	Grants the player a mega ring	None
grant_dynamax_band	LimitlessPixelmon	Grants the player a dynamax band	None