Perfect rhymes:
* bag
* cag (archaic)
* drag
* flag
* gag
* hag
* jag
* mag
* nag
* rag
* sag
* stag
* swag
* tag
* wag
Near rhymes (slant rhymes):
* alack
* back
* crack
* lack
* pack
* rack
* sack
* stack
* track
* whack
The best rhyme will depend on the context of your sentence.