I don't personally maintain much of an emergency fund, but if I were going to, I'd probably set up some sort of CD ladder to at least get as much out of the paltry interest rates as I could. Ally has CDs around 1.2% vs. their savings account which is 1%.
As for credit cards, if you want to start simple, I think one of the best plain-old cash back cards you could get right now is the Citi Double Cash card. It has 2% cash back on everything & no annual fee. There are other cards that offer 3% (sometimes more) on certain categories of purchases, but many have annual fees and it can get tedious trying to remember which card to use for which purchases to maximize cash back. If you want to go beyond simple cash back and start chasing bonus offers and other types of credit card rewards, /r/churning on reddit is a good place to browse.