Fair Labor Standards Act (FLSA): Federal law governing wages, overtime pay, recordkeeping, and minimum wage. Must be considered for any employment terms affecting compensation or working hours.

Civil Rights Act of 1964 (Title VII): Federal anti-discrimination law protecting employees from discrimination based on race, color, religion, sex, and national origin. Essential for ensuring addendum terms don't create discriminatory conditions.

Americans with Disabilities Act (ADA): Federal law requiring reasonable accommodations for disabled employees and protecting against disability-based discrimination. Relevant for workplace modifications or role adjustments.

Age Discrimination in Employment Act (ADEA): Federal law protecting workers 40 and older from age discrimination. Must be considered when modifying employment terms that could impact older workers.

Family and Medical Leave Act (FMLA): Federal law providing eligible employees with unpaid, job-protected leave for specified family and medical reasons. Relevant for leave-related modifications.

Equal Pay Act: Federal law requiring equal pay for equal work regardless of gender. Must be considered when modifying compensation terms.

Immigration Reform and Control Act: Federal law governing employment eligibility verification. Relevant for any modifications to work authorization or documentation requirements.

State Labor Laws: State-specific employment regulations that may exceed federal requirements. Must be reviewed based on the specific state jurisdiction.

State Minimum Wage Requirements: State-specific minimum wage laws that may exceed federal minimum wage. Essential for compensation-related modifications.

State-Specific Leave Laws: State laws governing various types of employee leave, which may provide additional benefits beyond federal requirements.

State Discrimination Protections: State-specific anti-discrimination provisions that may offer broader protections than federal law.

State Overtime Rules: State-specific regulations regarding overtime pay and calculations, which may differ from federal standards.

Non-Compete and Non-Disclosure Regulations: State-specific rules governing the enforceability of non-compete agreements and trade secret protections.

Internal Revenue Code: Federal tax regulations affecting employment relationships and compensation structures.

Worker Classification Rules: Federal and state guidelines for determining employee versus independent contractor status.

Employee Benefits Regulations (ERISA): Federal law governing employee benefit plans and their administration.

Occupational Safety and Health Act (OSHA): Federal law establishing workplace safety standards and employer obligations.

National Labor Relations Act: Federal law governing labor-management relations and protecting workers' rights to organize. Particularly relevant in unionized workplaces.