What group would be the best group to send money to help the following:

[texasfiddler]

Help with the ground efforts for the future Democratic Presidential Candidate in the swing states (Michigan, esp.Wisconsin, Pennsylvania, etc.). Is it the DNC? Swing Left? Some other group? Which one is the most organized and effective?

[bearsfootball516]

1. I imagine the official Wisconsin Democratic Party would be good.

Michigan and Pennsylvania will likely flip blue. But Wisconsin will be very close.

[yellowdogintexas]

2. I would agree: contact the state party

organization for the most flippable COngressional or Legislative districts and once the primary is over, donate to the nominee(s)

There may also be some grass roots organizations in these states that are running a coordinated campaign for several candidates and can give you information.
The Texas state party has already identified at least 12 Legislative districts which went for Beto in 2018 but the Republican candidate carried the district in single digit margins. Five of them are at least partially located in Tarrant County which went heavily for Beto anyway. We have an organization "Tarrant Together" which is running a coordinated campaign for all these House Districts. Each House District has a district co-ordinator to keep the precinct chairs connected.

Tarrant County has become a major focal point now for the National Party. The last red Metropolitan county in Texas went blue in 2018 and is poised to make a huge difference from now on.

If you live in Texas, you might want to check out Beto's new project to flip the Texas House. Organizers, donations are needed. We are poised to take back the Texas House which gives us tremendous clout at redistricting time.