If you're casting a seven mana spell freely, odds are you don't need to worry about losing the game
It turns out that there are more than a few creatures that get a lot better when you turn them into artifacts and give them a mana ability, especially if you want to give yourself a repetitive stress injury in your wrist by tapping and untapping Horseshoe Crab, Simic Ragworm, Soliton, or Morphling until they kick you out of the LGS
Starlit Soothsayer does exactly that, provided that youre losing or gaining life, and it fits many different archetypes
While it makes a big jump ahead of Winona, this Rayquaza is completely overshadowed by the most valuable card in Roaring Skies
In other words, youll be able to make 90% of the designs you have in mind here, but some of your fancier, more outlandish card designs probably dont have a compatible card frame
It too has some interaction in the form of redirects, but above all, it wants to see life totals melting as fast as possible