While FDR did many things in his first 100 days in office, I will name a few of the important things.
1. On March 31st he created the Civilian Conservation Corps.
2. On May 12th he created the Federal Emergency Relief Act.
3. On June 16th he created the National Industrial Recovery Act and the Emergency Railroad Transportation Act.
4. On May 12th he created the Agricultural Adjustment Act and the Emergency Farm Mortgage Act.
5. On May 18th he created Tennessee Valley Authority Act.
6. On June 16th he created the Farm Credit Act.
7. Farm March 9th to June 16th he also did many financial reforms, such as: Emergency Banking Act, Abandonment of Gold Standard, Government Economy Act, Securities Act, Home Owners Loan Act and the Glass-Steagall Act.
8. On March 22nd he also created the Beer-Wine Revenue Act.
Like I said before, there are many more, but those are the most important ones in my opinion. If you need more or any help with anything let me know! Have a nice day! :)