Path to Frogzile Rapid Hybridization, a functionally identical card to Pongify, playing on Path to Exile, which is similar to the above-mentioned Swords To Plowshares
Credit: Wizards of the Coast Synth Eradicator Steel Mentor: As mentioned in Nick Valentine's entry above, Synths are advanced androids developed by The Institute, the descendants of MIT scientists who holed up underground and have been playing around with advanced tech as the survivors on the surface fought tooth and nail to survive
This interview was conducted over email
Two of those are really useful as tools (Jace Beleren and Garruk Wildspeaker), two are really strong for casual play (Liliana Vess and Ajani Goldmane), and the last is Chandra Nalaar, the not-that-great at 5 mana
The original The Ozolith, printed back in Ikoria , sells for around $30