Short Words:
* an
* as
* at
* in
* is
* it
* king
* ink
* nag
* tan
* thin
* ting
* his
* shin
* sing
* ski
* hang
* tank
* than
* thing
Longer Words:
* thanks
* giving
* shanks
* gaskins (archaic word)
Note: This list isn't exhaustive, and there might be other less common words that can be formed.