10. Danny Tartabull (1987-91, 12.7 WAR)
Although, Danny Tartabull has most recently been in the news for a July arrest. He remains the only Kansas City Royals player to ever hit 30-plus home runs in a single season on two different occasions. Tartabull also tallied three 100-RBI seasons during his five years in Kansas City.
After finishing fifth in Rookie of the Year voting, Tartabull left Seattle for Kansas City. His first season with the Royals went better than anyone could have hoped. Tartabull finished the 1987 season with 34 home runs and 101 RBI. He also hit .309 while receiving a few MVP votes.
His home run numbers fell off the following season, as he hit just 26, but his RBI numbers stayed consistent (102). Tartabull labored through a pair of difficult seasons in 1989 and 1990—playing just 221 total games between the two campaigns.
In 1991, Tartabull rebounded to make his only All-Star Game appearance. He put up 31 home runs and exactly 100 RBI. Tartabull even led the league in slugging at .593. He finished 12th in MVP voting before joining the New York Yankees in the offseason.
His 124 home runs and .290 batting average rank in the top-10 all-time in Kansas City Royals history. He leads the franchise in career slugging percentage (.518) and OPS (.894).