My boyfriend pointed out these two fallacies, and now I feel like I see them everywhere!
Argument from future majority: "In a few decades, everyone will look back and see how wrong you were."
Hidden assumptions: Will people in the future in fact see how wrong you were? Is the majority opinion relevant? Are future people's opinions necessarily better than present people's opinions?
Combines: appeal to future evidence and argument from majority
Argument from hypothetical hypocrisy: "If she were a Republican, the right-wing would be dismissing this scandal as a distraction."
Hidden assumptions: Would the right-wing in fact do that? Does that necessarily mean that the right-wing's current actions are wrong, or could it just mean that their hypothetical actions are wrong? Do hypothetical wrongs of the right-wing justify similar wrongs of the left-wing?
Combines: begging the question and tu quoque
The nature of these arguments is that even if all parties were to agree on the hypothetical, the conclusions are still fallacious.