Flynns lawyer predicted that Trump would make novel and unusual use of presidential pardons

[GeoWilliam750]

2. Actually, Bush Senior pardoned several men involved in Iran-Contra before conviction

They had, however, been charged.

Also, Ford pardoned Nixon even though there had been no charges yet brought - to the best of my knowledge.

I am unaware of other cases, but it seems unlikely that the above were without precedent.

In the case of Flynn, my guess is that he would first have to be charged with something, and it sounds like they have quite a few things with which they could charge him. Thus, if Comey wanted to make this difficult for President Trump, he could charge Flynn with one thing at a time, starting with those charges bearing the shortest statute of limitations.