Edit: Adding Containment Construct after thinking about the basic curves it offers with The Modern Era and Akki Ronin as well as being a Reinforced Ronin setup
Sure, Katara, Waterbending Master is a mere 1/3, but blue decks already hold up interaction on opponents turns anyway, so accumulating experience is the easy part
Chart shows the price of Sauron, the Dark Lord [Borderless Poster] #744 at the end of each month going back as long as we have tracked the item.
Sky Hussar goes infinite with plenty of cards, one of the simplest gets you infinite mana with Eldrazi Displacer and dorks that tap for at least , one of which is a colorless mana
Myr Convert If you really want to destroy your life total, Myr Convert is an efficient piece of ramp that culls your life total as you cast spells and accelerates you towards payoffs and enablers