Looking for Great Multiplayer Co-Op Wads and Mods

This might be a cop-out answer to some, but I honestly think its the best, especially since you're trying to warm people up to the game. I have a few other recommendations but I think they're better for people who have a more robust familiarity with Doom since coop Doom can sometimes be a relay race and less experienced players get left behind.

You'll have to do a lot of testing to get the settings just right, but it has enormous potential for great coop slamfests:

Use the Oblige Level Maker

You can generate entire megawads. Make a quick playlist of midis in SLADE to add background music to the generated wad. It's probably really fun with gameplay mods too.

For example, friendly telefrags while going through teleports are an annoying thing in Coop and a lot of wads have them. so if you go into the level design control settings you can simply turn teleports off. You can also tell it to make short maps but with gigantic rooms. You can pick more or less of certain types of monsters, and you can turn ammo up so players never run out. You can also reduce doors and tell it to make maps into mostly vast caves and outdoor areas so its not very confusing.

The maps aren't always beautiful but they're definitely coherent. It's got working traps and secrets. The monster placement is sporadic and random but I do find it to be very fun most of the time. Sometimes you'll get some cool map ideas from playing the weird stuff it makes.

Seriously recommend generating single maps and tweaking settings though before making megawads to dump on your friends because it does take some time and resources to make a megawad, and if you fuck with the settings too much, you can certainly make 32 levels of unplayable garbage where you're surrounded by archviles in the starting room and the closest weapon is a chainsaw.

i think you should play alien vendetta in a co op

that sounds really cool , but can i play this in single player too ?