Across all the dictionaries we have on WordsRated, there are 265 words that start with BI.
With the words on this list you can score as many as 37 points in a game of Scrabble but the average score for a word on this list is 13.9.
The word that will bag those 37 points for you is BIZAZZES.
As the name would suggest, all of the 8-letter words on this list begin with BI but the most common final letter in the list is S. If you do not have S then words from the list become unavailable to you.
In this case, you might want to refine your search. If you place all of the letters you have in the from we can unscramble words from the letters, or you can take a look at our lists of 8-letter words with BI or words starting with BI.