Teval, the Balanced Scale Black Lotus Tezzeret, Cruel Captain Sheoldred, the Apocalypse Battle of the Rotted Tower Emberheart Challenger Tiamat Broodmate Tyrant Grist, the Plague Swarm Adult Gold Dragon Archon of the Wild Rose Time Walk Karn, Living Legacy Huntmaster of the Fells - Artist Series Craterhoof Behemoth Cyclonic Rift Blightsteel Colossus Elenda, the Dusk Rose Mox Opal Eternal Witness Ajani Steadfast Jegantha, the Wellspring Kozilek, the Great Distortion Lyra Dawnbringer Platinum Angel - Artist Series Sarulf, Realm Eater Sliver Gravemother Tivit, Seller of Secrets
Regulation Sets : specific set of rules that apply on top of the previous two
One of the most famous is energy, a mechanic that debuted with Kaladesh and swiftly overwhelmed Standard, which led to a slew of bans at the time
No matter which two modes you choose, you always follow the instructions in the order they're written