The mod that Youtubers use to show things?

[Hex:Feet]

How is this mod called which gives you these purple belts/chest... which have infinite resources? I want to test stuff but not in my main world.
Edit: I found one mod but not the one I wanted where literally everything is purple which is infinite.

[Pro Defamation League]

its called creative mod

[Premu]

No mod is needed, these items are available in the sanbox mode if you enable cheats. You have to add them using the console, for example:

/c game.player.insert{name="electric-energy-interface"}

This gives you an item which can either produce or consume as many electicity you want.

For the purple chests which can either create stuff out of thin air or destroy anything you put into them you have to enter

/c game.player.insert{name="infinity-chest"}

For fluids the equivalent is the infinity pipe:

/c game.player.insert{name="infinity-pipe"}

And there are the items loader, fast-loader and express-loader which can fill a yellow, red or blue belt completely.

This mode together with these items is a great way to play around with designs and to test them.

[RiO]

The mod you're looking for is called Editor Extensions[mods.factorio.com].

Originally posted by Pro Defamation League:

its called creative mod

Don't use that one. It's old and coded inefficiently.

[Leeux]

The mod you mention is called Editor Extensions[mods.factorio.com]!

EDIT: Lol... we both posted almost at the same time! :P

[Hex:Feet]

Editor Extensions was the one I was looking for, thanks!