Bitebtc is one of the popular scam exchange. They have scammed a lot of people, not sending the withdrawn amount. They have a self moderated thread here in the forum. Yobit is infamous exchange with it's shady behavior and a lot of ponzi running on site. A good place for pump and dump.
LAtoken is another large exchange being accused of shady behaviors. Liquid had some problems in the past but I guess are now solved. Bitforex too has a lot of accusation for the exchange of that size.