There are 11 words that start with 'blab'.
| blab | blabs | 
| blabby | blabbed | 
| blabber | blabbers | 
| blabbing | blabbered | 
| blabbering | blabbermouth | 
| blabbermouths | |
Note: These 11 words that start with 'blab' are found from the USA & Canada version of the tournament Scrabble word list.