Add a sound to all the buttons in a project

Just want to add to Jummit's answer above (which got me out a bind because I didn't plan ahead, assuming Buttons would have a built-in way to make a noise, thank you Jummit)...

Be sure to set your UISoundPlayer node to Pause Mode Process so that the sounds still play when the game is paused.

Another solution can be to make a new Scene, add an empty button to it, add a script to it and connect the pressed signal to sound_manager inside the init function. Then use this scene for every button which should make a sound. And, if the, sound is made an export var it can be customized in the editor.

This can be done using an AutoLoad script that connects to the "pressed" signal of all buttons in the tree.

Create a UISoundPlayer scene which consists of a node with an AudioStreamPlayer attached, which is used to play the UI sounds.

Add that scene as an AutoLoad, and attach this script to the root node:

extends Node

func _ready():
    # when _ready is called, there might already be nodes in the tree, so connect all existing buttons
    connect_buttons(get_tree().root)
    get_tree().connect("node_added", self, "_on_SceneTree_node_added")

func _on_SceneTree_node_added(node):
    if node is Button:
        connect_to_button(node)

func _on_Button_pressed():
    $ButtonSound.play()

# recursively connect all buttons
func connect_buttons(root):
    for child in root.get_children():
        if child is BaseButton:
            connect_to_button(child)
        connect_buttons(child)

func connect_to_button(button):
    button.connect("pressed", self, "_on_Button_pressed")

The code should be self-explanatory. It connects to all buttons on _ready and to newly added buttons.

Here is an example project: https://gofile.io/d/LTBvQf