ACE is always a nice realism mod to use, some real world things like Massi's AFRF and USAF mods to make stories out of like Russians take some islands and NATO responds, etc. Just some off the top of my head, there's probably way more out there that's even better.

The Community Upgrade Project (http://psteamcommunity.yuanyoumao.com/workshop/filedetails/?id=583575232) is a good one you will have some more maps,weapons,vehicles

Okay! ACE im familiar with. But then i have to choose between, CUP or Massi. CUP already have the maps, meanwhile if I choose MASSI i need AiA... Which is best, Massi or CUP?

CUP is only port from Arma 2, there are better mods for guns and etc.

CUP terrains is good! I'd suggest using maps from there, its a quick way for people to download ArmA 2 maps as they can use the workshop... more people would go for that. Weapons i'd suggest Massi however RHS:USAF/AFRF has some good units/vehicles as well as weapons....

this mission will be so ♥♥♥♥♥♥♥ awsome if you use all cups and ace and USA nevy seals clothing

ACE3 and RHSUSAF/AFRF are the best. Cup terrains are good but a huge download when most of the maps are repats of smaller areas of Rahmadi/Chenarus.

A nice huge sandbox to dig into is the Australia island by Ausisland. http://www.ausisland.com/ Complemented by the F/A-18X and Su-30(3?) mods and you're in for some fun. Hey toss in the Nimitz too, make a nice Marine story.

Thanks for all the suggestions! We will have a talk about these addons and create a mission! :)