Good rhymers make good readers! Rhyming is fun and educational.
Reinforce these phonics concepts:
short vowel sounds, long vowel sounds, consonant sounds, digraph sounds, blends, silent letters, syllables, onsets/rimes (word families), rhyming awareness
The spelling of rhyming words is not constant as in word families:
rhyming words - mate, wait, straight
word families - mate, late, rate
There is more rhyming fun here: Rhyming Word Fun Lists