Heather Cox: The indictment referred to six co-conspirators without identifying them by name, but the details included about them suggest that Co-Conspirator 1 is Trump lawyer Rudy Giuliani; Co-Conspirator 2 is lawyer John Eastman, who came up with the plan for then'vice president Mike Pence to use his ceremonial role of counting the electoral votes to throw the election to Trump; Co-Conspirator 3 is Trump lawyer Sidney Powell; Co-Conspirator 4 is Jeffrey Clark, a Justice Department lawyer whom Trump tried to push into the role of attorney general so he could lie that there had been election fraud; Co-Conspirator 5 appears to be Kenneth Chesebro, a Trump attorney behind the idea of the false electors.
The identity of Co-Conspirator 6, a political consultant, is unclear.

NYT: Messages Point to Identity of Co-Conspirator 6 in Trump Indictment

An email sent by Boris Epshteyn, an adviser to the Trump campaign, matches the description of an email that the indictment attributed to one of six unnamed co-conspirators.

Heather does a good job: <iframe src="facebook.com: Facebook" width="500" height="290" style="border:none;overflow:hidden" scrolling="no" frameborder="0" allowfullscreen="true" allow="autoplay; clipboard-write; encrypted-media; picture-in-picture; web-share"></iframe>