3 Letters:
* lep
* pre
* ran
* are
* her
* ear
* pen
* ape
* eon
4 Letters:
* arch
* each
* lean
* pane
* plan
* reap
* hear
* care
* earn
* chen
5 Letters:
* reach
* clean
* pearl
* crane
* cheap
* peace
* learn
* haunt
6 Letters:
* chance
* enchant
* reaches
7 Letters:
* preacher
8 Letters:
* preaching
This is not an exhaustive list, and there may be other words you can make depending on your interpretation of the rules. For example, you could use proper nouns or words that are not in common usage.