I know the 2 games below have 2 player couch coop. Not sure if you can play with 4p local on EDF

• Dynasty Warriors 8 - beat up soldiers by the hundreds while watching Romance of 3 Kingdoms as a 3D anime. "Complete Edition" but still has fuckloads of DLC skins which aren't worth it. Or just buy and pirate the actual complete thing later.
• Earth Defense Force 5 - Kill giant insects and aliens with building-destroying firepower. The story and narration in 5 takes itself too seriously, but it has many quality of life improvements over 4, which is overall a funnier game with the best infantry sing-along

Which ones have you heard of?

• Gauntlet Slayer Edition
  • Good old dungeon crawling. 2014 revival of an 80s arcade classic.
• Keep Talking and Nobody Explodes
  • Defuse a bomb with your friends
• CATO: Buttered Cat
  • Puzzle platformer featuring that joke about how cats and toast land when dropped
• Mosa Lina
  • Aggressively randomized puzzle platformer
• Assault Android Cactus
  • Arcade-style twin-stick shooter with pumping soundtrack
• Pizza Possum
  • Very soft stealth game about stealing and eating lots of food
• Moving Out 2 (or 1 if you're fine with local only)
  • Drag and move furniture onto a truck

Relevant?

Tinkerlands. I just got it together with Novalands (which is a good time sink on switch). Haven't started playing it yet, but it seems similar to terraria, but topdown and with more focus on coop.

If you can forgive the self promotion and enjoy platformers. Our game has (an admittedly challenging) couch coop mode.

https://store.steampowered.com/app/1771200/Cat_Box_Paradox/

Depends on which you did hear of. Spelunky you probably did, but is Octodad niche enough?

Ooh, try Full Metal Furies. I personally mostly played single player, but I think co-op should be cooler, though I only played a few stages.