WYSK: There funded by dark money PACS, but some good reporting has brought out these names: David Koch, Peter Thiel, Reid Hoffman, Mark Cuban, Harlan Crow, and Michael Bloomberg. Some of there members are most famous for stopping big bills. Joe Leiberman, for example, single handedly stopped the single payer portion of the ACA. Senators Joe Manchin and Kyrsen Simena kept the John Lewis voting rights act from passing, and famously kept the senate from repealing the filibuster.
Elected officials from both parties almost always seem to all vote for the same as the rest of their party and even at times vote against the opposing party only because the opposing party is voting for it.