28. Adam Ottavino (Rockies Career WAR 9.2)
Otto is a shining example of what can be done by a talented former 1st-round flamethrower when unleashed in short stints.
He was for the Rox and continues to be for the Yanks an absolutely dominant reliever with a Bugs Bunny slider. The only other pitcher I have ever seen throw a better slider was Randy Johnson, yes, that Randy Johnson. I believe with a bigger market in New York he will start getting the recognition he deserves.
His best year in Denver came in his last (2018), when he pitched to the tune of a sparkling 2.45 ERA, won 6 games, 6 saves (finishing 16 total), while striking out an insane 112 batters in just 77.2 IP for a ridiculous 13 K/9 and 195 ERA+ for the playoff-bound Rockies.