TI also has their LDC1xxx range. They're very capable sensors, but finicky. If the environment is just right, you can get some impressive accuracy out of them. If the environment is not so good... well, your measurements will tell you a lot about said environment!
One of the more interesting things is that there are two viable types of target: conductive materials and magnetizable materials. They have opposite effects on mutual inductance, and therefore on sensor reading. This can make for some interesting debugging.