Not sure if you mean "bundlers" by its technical definition, b/c Warren didn't have such a program in 2020. As for the super PAC backing her with $14M, yes I encourage folks to read Ryan Grim's book "The Squad" on the primary. What's more, we analyzed a large dataset covering first half of 2019:
Wealthy, White, and Over 50: The Demographics of the Democratic Presidential DonorsSludge and Data for Progress analyzed the Democratic presidential candidates' donors by income, race, gender, age, and ideology.readsludge.com