Ever heard of Lady's Secret?
Lady's Secret won the 1988 Preakness. Secretartiat also sired Belmont winner Risen Star, and the 1990 Melborne Cup winner Kingston Rule.
Also , he also sired General Assembly who won the 1979 Travers Stakes at Saratoga while setting a still standing race record of 2:00 flat.
Secretariat has received some criticism as a stallion due in part to his perceived inability to produce offspring of his calibur. His expensive syndication deal, perhaps, raised unrealistic expectations. He sired as many as 699 foals during his retirement.
Secretariat is also the dam-sire of Storm Cat through his daughter Terlingua, and excellent race mare, and of Gone West, through his daughter Secrettame.