Part of the value of Toxic Deluge is that life is less risky to pay in powered formats, an extra turn of speed is more valuable, and the tactical applications of Toxic Deluge are quite important
Character cards that only cost two and can quest for three lore are very few and far between
Key Cards: Food Chain - infinite mana and tokens on repeat
Then, left unchecked, this will just win games This can be used to rebuy ETBs and Adventures, which is cool
For example, if an effect allows you to put a creature card from your graveyard onto the battlefield, you can put Halvar, God of Battle onto the battlefield
Shes basically the ultimate Spike card, with options, resource manipulation, attrition, synergy, an enormous amount of play, and incredible at quieting games down and making them about knowable enough of things that someone very dedicated can actually have a handle on most everything