Perfect rhymes:
* beguileful (archaic)
* dutiful
* fruitful
* youthful
Near rhymes:
* beautiful
* doubtful
* helpful
* thoughtful
Eye rhymes:
* peaceful
You can also use words that have a similar sound but aren't perfect rhymes, such as:
* cheerful
* joyful
* sprightly
* lively
The best rhyme will depend on the context of your writing or speech.