Alliant Credit Union is one of the nation's largest credit unions and is based in Illinois. While membership is technically restricted, it's actually very easy to qualify. For example, a $5 donation to Foster Care to Success (that Alliant will actually pay on your behalf) will grant you and any immediate family members of yours lifetime membership.
Alliant has won several notable awards in recent years, from best overall credit union (CNBC) to best online experience (NerdWallet). They offer competitive rates (particularly their mortgages and auto loans), a solid digital experience, and coveted credit cards. With their ATM fee rebates, they even tout that they have more ATMs than Chase and Bank of America, combined (80,000!).