FETs and BJTs are both common for analog. Discrete analog tends to prefer BJTs, which (among other features) have much higher transconductance, which you can never get enough of. FETs offer ultra-high input impedance, better performance at low power (though BJTs ain't all bad there), and the big one... they're built on CMOS processes. That means you can integrate your analog stuff with a giant pile of digital logic, which is a tremendously useful thing to do. (But the analog section alone often would be better if it were on a bipolar process.) Op-amps are split evenly between both types. Okay, evenly-ish.