After I left my former employer, Chase converted my employer-sponsored HSA into a fee-ridden mess. I rolled my contributions into Alliant Credit Union. They have impressed me so far - they pay a decent rate, don't tack on BS fees, and have 24/7 phone support. It is fairly easy to join as a member of the many Qualifying Organizations.
Other organizations may have HSAs with different advantages, particularly in the realm of investment options. I picked this simple option due to my low balance and their good reputation and competitive rate (1.25% APY right now on balances $100 or more).