There are 20 words that start with 'seat'.
| seat | seats | seated | 
| seater | seaters | seating | 
| seatback | seatbelt | seatings | 
| seatless | seatmate | seatrain | 
| seatrout | seatwork | seatbacks | 
| seatbelts | seatmates | seatrains | 
| seatrouts | seatworks | |
Note: These 20 words that start with 'seat' are found from the USA & Canada version of the tournament Scrabble word list.