I've found a system for MLB that plays only favorites. The favorites have to be -140 or better to qualify. Betting on favorites at those numbers is very risky business and almost certainly doomed to fail but not all those teams will qualify as a play and it's hard to argue with the results. This system has been profitable when playing on the Moneyline, Runline, and the Ov since 2014.
Results from the 2014 season:
ML - 45-17 (72.6%) +19.72un
RL - 36-25 (59%) +14.96un
Ov - 35-23-3 (60.3%) +9.9un
Results from the 2015 season:
ML - 29-20 (59.2%) -1.89un
RL - 25-24 (51%) +3.41un
Ov - 27-21-1 (56.2%) +3.92un
Results from the current (2016) season:
ML - 11-1 (91.7%) +9.37un
RL - 9-3 (75%) +6.68un
Ov - 10-1-1 (90.9%) +8.95un
This system doesn't provide a huge number of plays but has churned out a steady profit for the last two seasons. I'm a little nervous about tracking now due to the extremely high win rate of the current season because it must regress sooner or later but will hopefully continue to follow the trend from the past two seasons when the dust settles. So I will use this thread to track this system for (hopefully) the remainder of the season.
*I don't have past data to investigate but I will also be tracking the Team Total OVER in this thread for each play.