8. Defeated Pralaya - Justice League Dark #40
You would think taking on a being as big as Pralaya would net someone and pulling the wool over their eyes would net you a higher spot, but though this victory belongs to Constantine, it's only partly.
Some context: at the end of The New 52's run of Justice League Dark - the branch of the League that deals exclusively with supernatural threats - the team comes up against their biggest foe yet, Pralaya. Simply put, she is the embodiment of the nothing that exists between big bangs, and she's decided to bring about her endless nothingness quite a bit early by eating Yggdrasil The World Tree.
And she succeeds, seemingly killing the League and literally everyone, everywhere. Well...crud.
Except not really, as this was all an elaborate plan set up by Constantine and Zatanna. Since they knew trying to fight Pralaya directly would be rather dumb, Zatanna goaded her into eating them along with The World Tree. once inside, Constantine reseeded the tree, allowing it to grow to its former glory from inside her, restoring everything and repelling Pralaya.
Not 100% his plan, which is what keeps such a monumental feat from any higher, but it couldn't not be mentioned.