I think this is a good overview of where Mueller might be going as far as charges that relate to collusion/conspiracy/collaboration with the Russians.
https://www.justsecurity.org/53241/russians-previewed-plan-disseminate-emails-trump-campaign/
There are a number of associates of Trump's who I believe will turn out to have been witting collaborators.
Three have already pleaded guilty to other charges and are cooperating: Papadopoulos, Flynn, Gates
Another is probably also cooperating: Sater
The others who for various reasons I think are in legal jeopardy specifically with respect to collusion/conspiracy/collaboration (including concealment): Manafartov, Cohen, Kushner, Trump Jr, Erik Prince Superstar, Hope Hicks, Carter Page, Roger Stone. And of course Trump himself. This is the core group. I suspect when all is said and done the list of American collaborators will be bigger.
Many in this group are also in legal jeopardy with respect to other aspects of Mueller's investigation.