Where can I learn more about Health Savings Accounts (HSA) and Health Reimbursement Arrangements (HRA)?

Publication 969, Health Savings Accounts and Other Tax-Favored Health Plans
This publication includes information on Health Savings Accounts, Medical Savings Accounts, Flexible Spending Arrangements and Health Reimbursement Arrangements.

Publication 15-B 
This publication supplements Pub. 15, Employer's Tax Guide, and Pub. 15-A, Employer's Supplemental Tax Guide. It contains information for employers on the employment tax treatment of fringe benefits, including Health Savings Accounts and Qualified Small Employer Health Reimbursement Arrangements.

Health Savings Accounts - Contribution Limits 
Revenue Procedure 2018-18 (dated March 5, 2018) lowered the HSA contribution limit for individuals with family HDHP coverage to $6,850. Revenue Procedure 2018-27 (dated April 26, 2018) raised that limit back to $6,900.

Rev. Proc. 2018-30 - IRS.gov 
This revenue procedure provides the 2019 inflation adjusted amounts for Health Savings Accounts (HSAs).

Heath Reimbursement Arrangements – State and Local Government Health Plans
The Protecting Americans from Tax Hikes Act provides a limited exception for certain HRAs that reimburse the medical expenses of a deceased employees’ beneficiary.

Notice 2017-67 
Qualified Small Employer Health Reimbursement Arrangements (QSEHRA) This isn’t a group health plan, and, therefore, isn't subject to group health plan requirements. This notice provides guidance on the requirements for providing a qualified small employer health reimbursement arrangement (QSEHRA), the tax consequences of the arrangement, and the requirements for providing written notice of the arrangement to eligible employees.