Common words:
* Fox
* Box
* Ox (the animal)
* Tax
* Knox (a surname)
* Hex (a curse)
* Fix
Less common words:
* Apex (the highest point)
* Faux (artificial, fake)
* Prox (short for "proximity")
* Buxom (plump and attractive)
* Cadox (a type of chemical)
* Dox (a type of software)
Informal words:
* Blox (a type of toy block)
* Pox (a disease, often used in slang)
* Gox (a slang term for a bad situation)
Let me know if you'd like more words, or words that fit a specific category!