How can I use addons from a multiplayer server in singleplayer?

[8Bit_Coder]

I've joined a few servers and each have amazing addons, except I can't get them into singleplayer. I really would like some of the addons to be usable in singleplayer so I can mess around with them. I already tried copying the files from the server downloaded folder into the addons folder but none of them show up. Can anyone help?

[imphonic]

They might be special required addons.

[imphonic]

You might not be able to run those addons in singleplayer.

[Lukyn150]

Find their content pack and cownload the addons. If they don't have the one you want there ask someone on the server about it. If it's a server custom made addon you can not use it. It's probably incompactible with normal Gmod.