Perfect rhymes:
* tester
* vester (archaic word meaning "one who clothes or provides clothing")
Near rhymes:
* quester (one who searches)
* guster (a gust of wind)
* luster (shine or brilliance)
* master
* faster
Eye rhymes:
* chester (a city in England)
* gesture
The best rhyme for you will depend on the context of your writing or speech.