Non-MLB
Although they have not thrown an MLB pitch in 2024, David Holmberg threw 2,229 pitches that were tracked by the PITCHf/x system between 2013 and 2017, including pitches thrown in the MLB Regular Season and Spring Training. In 2017, they relied primarily on their Fourseam Fastball (88mph) and Sinker (88mph), also mixing in a Change (82mph), Slider (81mph) and Curve (73mph). He also rarely threw a Splitter (89mph).
In 2017, compared to other LHP:
Their fourseam fastball has below average velo and has some natural sinking action. Their sinker has less armside run than typical, results in somewhat more groundballs compared to other pitchers' sinkers and has slightly below average velo. Their change dives down out of the zone. Their slider generates fewer whiffs/swing compared to other pitchers' sliders. Their curve has an exceptional bite, generates fewer whiffs/swing compared to other pitchers' curves, has slight glove-side movement and has slightly below average velo. Their splitter (take this with a grain of salt because they've only thrown 1 of them in 2017) is thrown extremely hard, is basically never swung at and missed compared to other pitchers' splitters, is an extreme flyball pitch compared to other pitchers' splitters and has movement that suggests a lot of backspin.