I recently found Chow Cafe & Bar inside Metrople Hotel, it was open late, until about 4am and was jam packed with party peoples!
They have food, billiards, drinks and last call was around 3:30am. Pretty nice place to hitup on the late night in Bangkok night times!
Address: Metropole Hotel ( Thonglor Pier ) Thong Lor / New Petchaburi Road, 2804, Bangkapi, Huaykwang
Bangkok, Thailand 10310
Address: 2802 New Phetchaburi Alley, Khwaeng Bang Kapi, Khet Huai Khwang, Krung Thep Maha Nakhon 10310
Facebook: https://www.facebook.com/CHOW.Bangkok/