RR (Rickey Runs)- any run scored by Rickey Henderson or in a Rickey manner. The most common formula for RR is R+SB+BUNT/130.
WaRI (Wins above Raul Ibanez) – see here.
LMF (Lastings Milledge Fact)- any completely true statement found at Milledge Facts.
BH (Blown Hold)- introduced in order to quantify what Scott Schoenweis does
HR* (Home Run*)- similar to a normal home run, but hit by Barry Bonds
GB% (GyroBall %, formerly Ground Ball Rate)- the percentage of pitches thrown by Dice-K that gyrate (see also GB/9)