Similar to "tremble":
* Quiver: A slight, rapid shaking.
* Shake: A more forceful shaking.
* Shiver: A trembling caused by cold or fear.
* Flutter: A rapid, light shaking.
* Wobble: A shaky, unsteady movement.
* Jiggle: A quick, jerky movement.
* Shudder: A sudden, violent tremor.
Similar to "vibrate":
* Oscillate: To move back and forth regularly.
* Pulse: To beat rhythmically.
* Hum: To make a low, continuous sound.
* Buzz: To make a high-pitched, continuous sound.
* Throb: To beat strongly and rhythmically.
* Undulate: To move in a wavelike motion.
The best synonym will depend on the specific situation and the desired level of intensity.