You know, I find myself searching desperately for coop games that my friends and I can play almost nonstop. Finding good ones is just so difficult-- and since you have to purchase the game twice, once for you and once for your friend, it makes it even harder to find a reasonable price for a quality product.

So, I've made this list!

If anyone else looks for coop games and always seems to struggle, which I don't know--maybe nobody does, but if they do, this will be sure to help!

I'm going to list all of the very best coop games that I myself have played. I'm sure there are some other amazing ones out there, but I may not have played them and so I don't want to put them into a list!

Terraria.

Think 2d Minecraft, except a lot better. You can invite your friends to play this game through steam or play singleplayer, though having a friend makes everything more fun.

What you can do in this game:

• Mine for minerals, explore caverns.
• Build houses, or anything else you want to make.
• Fight massive BOSSES, and not just one or two but OVER 10 for different loot.
• Go to hell, go to space, find sky islands--basically, you can do anything in this game.

ASTRONEER.

This one is still in early access, and one of the biggest cons about it is that there isn't that much content in the game yet-- and there's a lot of bugs. One of the more amusing ones was an infinitely-sliding animation glitch, which gave us some good laughs.
This game is absolutely beautiful, about being in space. You mine minerals, make vehicles, spaceships, and travel around the galaxy. The graphics are truly beautiful.
Many people say this game is "what No Man's Sky" should have been. I'm not sure, judge for yourself!

Tabletop Simulator

Tired of all this combat?
Well, this is the game for you.
It might seem kind of irrelevant-- why not just get your own boardgame and table, and make this game irrelevant? Well, you can get any board game you can imagine on this game, through Steam Workshop. And it's a fantastic game to play alone if you have noone to play with! There's voice chat, so you can hop in a server (my personal favorite game people play on here is called Secret Hitler, truly amazing) and play!

If you feel like doing a massive jigsaw puzzle with a picture of YOUR face on it, that's totally doable! Or want to play an endless game of monopoly? It's got you covered. No trailer for this one because I feel like it's pretty self-explanatory.. but trust me, it's a good game!

Trine 2

This game is honestly the prettiest thing I've ever seen. The lighting, the graphics, are just heavenly.
And it's also amazing for playing with a friend, or two!
It IS a puzzle game, so be prepared to exercise your brain power. You get to play as a wizard, a bow girl who has a grappling hook, or a warrior who can kill enemies. You've got to work together, or switch between characters, in order to get through all the puzzles!

It sounds kind of lame, and one of the biggest cons about this game is that it gets a little repetitive, but it is good!

Sid Meier's Civilization V

This is a good game to play with, or against, your partner.
It's a turn-based RTS, where you are a nation exploring and growing to basically take over the world. There's different ways to win, so if you're not into invading, you can focus on defence and grow in knowledge as you pass through the different ages.

These games last quite a long time, so if you go into a large map with 4 different other people, be prepared to invest hours into this game. The replayability is almost endless as well!

Don't Starve Together

If you like Terraria or Minecraft, you'll probably like this. As the name suggests, this is a survival game where you try not to starve.. together! You can make different crafting stations, make technology and collect resources. There's different seasons, so difficulty is sure to continue getting more and more great as you go along--don't freeze to death in winter!

I'm personally terrible at this game, though I really enjoy it. I've never got past the first year! That's my fault though- I always start a world, get about halfway through and then die or give up. I'm horrible!
Good to note there's a singleplayer version of this game which is just Don't Starve, but you can technically play Don't Starve Together by yourself too if you just make a server and set a password.
Another thing is that the artstyle is quite goofy but really nice, in my opinion. Here's a trailer.

Honorable Mentions:

Awesomenauts (free to play!)

Overwatch

Team Fortress 2 (also free to play!)

Fortnite (free battle royale, pay for coop vs enemies)

League of Legends (free to play!)

The only reason these aren't on the real list is because they're not technically Coop, for example Overwatch you're on a team with other people but you can just invite your friend to be one of your teammates. League of Legends and Team Fortress 2 is the same thing.
They are truly amazing games though, and you've probably heard of them. I've sunk hundreds of hours and dollars into League of Legends, because while it's free to play, they sell cosmetics for their characters which sometimes I just can't help but purchase!

Happy gaming!
<3