While most applications will use a crystal oscillator, two options may be a better fit for your design: ceramic resonators and surface-acoustic-wave (SAW) resonators.
Ceramic resonators are piezoelectric components made from materials other than quartz, like lead zirconium titanate (PZT). These devices are smaller than crystals and have a tolerance of about 0.5%, compared to the 0.001% or better tolerance of a quartz crystal. Where precision is only marginally important, a ceramic resonator will work nicely at much lower cost. A common application is the clock in an embedded controller.
A SAW resonator uses an inter-digital transducer on a quartz substrate. SAW devices are used mostly for UHF/microwave filters, but they can also work as the frequency-determining component in a oscillator. These oscillators usually operate at frequencies in the 300-MHz to 1-GHz range, beyond the range of most crystal oscillators. They can produce good precision (±100 ppm) and low phase noise.
