Here is the full list of all 19 R.B.I. Baseball 18 achievements worth 1,000 gamerscore.
Hit back to back to back home runs in Derby
Complete full season in Franchise Mode
Complete Trade with CPU in Franchise Mode
Complete all gameplay tutorials
Rob a home run -- any mode
Win the HR Derby against CPU
Hit 1000 RBIs (any mode)
Hit a grand slam with a Legend player
Win a Complete Game with a single Legend Pitcher
Score a run after tagging up on fly ball vs CPU or Smart Match
Score an RBI on a walk vs CPU or Smart Match
Win an Online Smart Match
Beat the 2017 Wins leader: 19 Wins in a season with a single pitcher
Beat the 2017 HR leader: 60 Home Runs in a season with a single player
Beat the 2017 Stolen Base leader: 61 Stolen Bases in a season with a single player
Win a game on a Suicide Squeeze (runner leaves 3rd before contact on a bunt) vs CPU or Smart Match
Tag a runner out in rundown using pump fake (Smart Match only)
Turn double play on a comebacker to pitcher vs CPU or Smart Match
Win the World Series (Franchise Mode only - no simmed games during season)