Martin Luther King Jr. Day (January)
https://en.wikipedia.org/wiki/Martin_Luther_King_Jr._Day

Equal Pay Day (Varies)
https://en.wikipedia.org/wiki/Equal_Pay_Day

Cesar Chavez Day (March)
https://en.wikipedia.org/wiki/Cesar_Chavez_Day

Worker’s Memorial Day/Week (April)
https://en.wikipedia.org/wiki/Workers%27_Memorial_Day

International Worker’s Day (May)
https://en.wikipedia.org/wiki/International_Workers%27_Day

Classified School Employees Week (May)
Classified School Employee Week is celebrated on the third full week in May each year, from Sunday to Saturday.

Labor History Month (May)
https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=EDC&sectionNum=51009.&article=1.

Labor Day (September)
https://en.wikipedia.org/wiki/Labor_Day