There are 11 words that end with 'thon'.
python | benthon |
marathon | telethon |
phonathon | talkathon |
trilithon | walkathon |
autochthon | anacoluthon |
ultramarathon | |
Note: These 11 words that end with 'thon' are found from the USA & Canada version of the tournament Scrabble word list.