Demonic Dread, a Cascade card that makes a creature unblockable, has gone up in price a tad - and foil copies are suddenly super expensive - but it looks like most Modern players are sticking with the Azorius option
Ancient Copper Dragon Copper dragons are pranksters and jokers who appreciate sense of humor
The biggest danger is that almost every deck sideboards Karn, rather than that Karn just beats everyone, and I think theres a good chance that wouldnt force them to ban Karn, although theres a small chance that that would push the price of Karn high enough to chase some people out of the format.
Surly Badgersaur This dinosaur will fight another creature provided that you discard a non-land, non-creature card
Red also has some access to Wheel of Fortune type effects so like blue it can have limited card quality discard effects
That is why using multiple tests is essential