There are a total of 66 7-letter words containing 'by', and the number may vary in different dictionaries. You can specify the dictionary and order.

• abysmal ₁₆
• abyssal ₁₃
• abysses ₁₂
• babying ₁₈
• babyish ₁₇
• babysat ₁₅
• babysit ₁₅
• blowbys ₁₉
• bycatch ₂₀
• byelaws ₁₆
• bygones ₁₅
• bylined ₁₅
• byliner ₁₄
• bylines ₁₄
• bynames ₁₆
• bypaths ₁₇
• byplays ₁₈
• byrling ₁₆
• byrnies ₁₃
• byroads ₁₃
• bytalks ₁₇
• bywords ₁₆
• byworks ₁₉
• byzants ₂₂
• crybaby ₂₀
• exabyte ₁₉
• forebye ₁₅
• goodbye ₁₅
• goodbys ₁₅
• hushaby ₁₇
• lobbyer ₁₆
• lullaby ₁₆
• mangaby ₁₈
• qubytes ₂₂
• rockaby ₁₉
• rubying ₁₆
• rudesby ₁₄
• sassaby ₁₂
• scrubby ₁₉
• shrubby ₁₈
• sibylic ₁₆
• squabby ₂₅
• standby ₁₄
• swingby ₁₈
• tarbaby ₁₅
• thereby ₁₄
• tobyman ₁₆
• tobymen ₁₆
• vasbyts ₁₆
• wallaby ₁₇
• whereby ₁₇
• abyeing ₁₃
• bycoket ₁₈
• bylanes ₁₂
• bynempt ₁₆
• byplace ₁₆
• byreman ₁₄
• byremen ₁₄
• byrlady ₁₆
• byrlaws ₁₅
• byrooms ₁₄
• byssine ₁₂
• byssoid ₁₃
• bywoner ₁₅
• lewdsby ₁₆
• trilbys ₁₂

There are 66 7-letter words containing by in the well-known word game dictionary, 47 in the Scrabble US (US/Canada/Thailand - TWL/NWL) dictionary, and 62 in the Scrabble UK (International - SOWPODS/CSW) dictionary, and 51 in the Words with Friends (WWF) dictionary.