Standard is the least certain of the bunch, mostly because cards like Magma Spray and Abrade offer the ability to remove every one-mana creature along with some two- and three-mana creatures as well, but when you consider that the next-best options in white are cards like Gideon's Reproach and Slash of Talons (discounting enchantment-based removal like Seal Away, which is probably already in your main deck), the flexibility of killing one-drops and random sideboard hate might be enough for Isolate to sneak into sideboards in small numbers
Judges can require you to swap them out, which isnt ideal if your tournament deck is all foils
The big breakthrough I made with the day/night design was a double-sided day/night card that represented whether it was day or night
Bonus: What Card Has the Highest Mana Value
It can already do all the things Red does
If you choose the same opponent that Blitzwing, Adaptive Assailant had connected with, that player will lose at least 3 more life