This 6 gate inverter chip with input hysterisis is often used as the core of Microcore circuits.
It's also useful for signal conditioning, and inverting signal polarities.
The 74AC14 and 74ACT14 contain six inverter gates each with a Schmitt trigger input. They are capable of transforming slowly changing input signals into sharply defined, jitterfree output signals. In addition, they have a greater noise margin than conventional inverters.