Common words:
* back
* black
* clock
* duck
* kick
* luck
* pack
* rock
* stick
* track
Less common words:
* bicker
* brick
* clack
* click
* crick
* hick
* kickback
* knock
* pluck
* slick
* stock
* tack
* wicket
Let me know if you'd like more words, or if you're looking for words with "ck" in a specific context.