[MayflowerMadam]

“It doesn’t even have to reference a specific event. It can be for any federal crimes committed during a specific time period.”

I think that’s true. Didn’t Ford pardon Nixon, even though he hadn’t been convicted of anything? Didn’t it cover anything that might arise in the future?

I may be totally wrong, but that comes to mind for some reason.

[DesertRhino]

Exactly right. He was pardoned for a specific period of time.

[TChad]

I may be totally wrong...,

Nope, you are totally right.

https://www.forbes.com/sites/jacobfrenkel/2017/07/21/president-trump-can-preemptively-pardon-his-advisors-and-family-but-will-he/#6de1e72a6c3b

In an opinion issued in 1886, the Supreme Court clarified that the pardon power conferred by the Constitution is “unlimited, with the exception [of cases of impeachment],” and it “extends to every offence known to the law.” The Supreme Court wrote that the President may exercise the pardon power after the commission of the criminal offense, before or during legal proceedings, and after conviction and judgment. In fact, so long as the President grants a pardon before conviction, then doing so prevents any of the “penalties and disabilities consequent on conviction from attaching” to the pardoned person.

Presidents can only issue pardons for federal crimes, not state crimes.