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
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
Sure, you cant fall back on discarding cards or sacrificing lands, but twice the power per card invested makes this a significant threat fast
Key Cards: Food Chain - infinite mana and tokens on repeat
Even if you can't get the second 5/5 dragon with this, it's a good card -- and Red decks will often be able to make this card reach it's ceiling, at which point it's pretty close to unbeatable
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