Urza, Lord Protector is an obvious place to start, discounting all the non-creature (and non-planeswalker) spells you want in that kind of deck
For some sets the reverse slot would be impossible to fit in one sheet I am pretty sure
In Constructed, your Contraption deck needs at least fifteen different Contraption cards, and no more than one of each
Theres so many powerful abilities from Magics expansive history that have some sort of combat or enter the battlefield, or even activated ability that Delney can duplicate, making it an instant vital card for many decks.
It continues its research into the mystical beings known as "espers" in a bid to create ever more terrible Magitek weaponry
Kethis, the Hidden Hand Kethis, the Hidden Hand is a graveyard-loving legend that reduces the cost of all your legendary spells and lets you reuse them from the graveyard