What are some must have garrys mod mods?

What are some must have garrys mod mods? im looking to just have some fun and mess around+maybe make some scenario's like wars or something. im new to garrys mod. PLEASE let me know some good mods/packs/models/skins/anything you can think of for garrys mod i know that there is alot. but let me know your suggestions, links would help too. so far the only website i know to get them at is garrysmod.org