My understanding is that they must be issued individually for a specific crime or charge.

Interesting things about his pardon for Steve Bannon: apparently it's flawed and may not stand up to a challenge in court, and apparently pardons can be challenged! Also, Bannon's charges can also be applied at a state level, so it would be no problem for the Feds to send all the material they've gathered to State prosecutors - and bonus, the state penalties for what he did are stronger than the Fed penalties!!!