MEMS are awesome! Here are some other MEMS devices:

- hard drive read/write heads (the platters are debatable)

- inkjet printer nozzles (this is why making a DIY inkjet printer is nontrivial)

- air pressure sensors (e.g., for car tires)

- precise frequency filters for smartphone wireless communication

- oscillators (https://news.ycombinator.com/item?id=18340693)

- very tiny microphones for smartphones (speakers are harder)

- Digital Micromirror Devices (DMDs): arrays of tiny mirrors used in most projectors

- microfluidics ("lab-on-a-chip" stuff for fast disease testing, DNA sequencing, cell manipulation, etc)

And a couple other semiconductor applications:

- LCD/LED screens (monitors, phones, laptops, etc) (these are made on a glass surface instead of a silicon wafer but use the same basic manufacturing techniques)

- laser diodes (laser pointers, CD / Blu-ray players)

- many quantum computers