"A" and "B" books are recommended.


"A" rated books
nitrogensports.eu A+ (2013)  
betcoin.ag A (2013)            

"B"rated books
bitcoinrush.io B (2013)
mBet.io B- (2017) Horse racing.      

"C" rated books
betbtc.co C (2014)
fortunejack.com C (2019) sportsbook, (2014) casino.            
anonibet.com  C- (2011)      
jetwin.ps C- (2013)
playbetr.com C- (2019)

"D" rated books  
bitgame.online D+ (2017)
cloudbet.com D+ (2013)        
coinbet24.com D+ (2015)  
parlayplus.com D+ (2019)    
1xbit.com D (2016)  
dbet.io D- (2019)