Taking down Thanos isn't an easy feat - even for The Avengers. Rarely does Marvel's biggest bad let his guard down, meaning in order to stop him, superteam's need to get creative. However, once a new version of the Fantastic Four figured out the best way to deal with Thanos was to get inside his head.
Marvel's What If? series reimagined big moments outside continuity, including "What If Spider-Man Joined the Fantastic Four? What If Captain America hadn't Vanished in World War Two?" and "What if Dazzler had Become the Herald of Galactus?" Some stories inspired future in-continuity storylines, such as "What If Jane Foster had Found the Hammer of Thor?" The series is even being adapted for an animated show on Disney+. One of the newer versions of What If? tells the story of a new Fantastic Four and their quest to stop Thanos.
What If... Newer Fantastic Four (2009) by Paul Tobin, Patrick Scherberger, Craig Yeung, Chris Sotomayor, and Nate Piekos, told the story of a world where the Fantastic Four had perished and a new team consisting of Spider-Man, Ghost-Rider, Hulk, Wolverine, and Iron Man became the new Fantastic Four. However, during a fight with Kang the Conquerer, half of humanity (including Ghost-Rider) is snapped away by Thanos - who wielded the Infinity Gauntlet. The group take matters into their own hands, declining help from Adam Warlock, Doctor Strange, and Silver Surfer in order to pull off their own plan.
Surprisingly, the group's plan works. Wolverine relates to Thanos by talking about a love he can't have (Jean Grey and Death, respectively). Meanwhile, Wolverine gets Thanos to erase Mephisto by tricking the Mad Titan into believing the devil was also after Death's hand. On Earth, the rest of the new Fantastic Four use the armor of a fallen Celestial to build a superpowered Iron Man armor. They manage to catch Thanos off-guard, but after an initial attack, Thanos deals with Iron Man without a problem. However, as the fight occurs Wolverine convinces Thanos to touch Death's face for the first time. As he's about to, Wolverine cuts Thanos' gauntlet-wielding arm clean off. Spider-Man picks up the Infinity Gauntlet and undoes the snap.
Honestly, what made the new Fantastic Four so effective was their unwillingness to play by the rules, effectively ignoring Adam Warlock's warning and each other, in order to surprise Thanos when he least expected it. While Thanos snapped half the universe out of existence, the new Fantastic Four undid his actions much quicker than The Avengers have in either the comic universe or the Marvel Cinematic Universe - and with just four heroes! When it comes to dealing with Thanos, there's nobody better, apparently.