Although he has not thrown an MLB pitch in 2019, David Hess threw 1,750 pitches that were tracked by the PITCHf/x system in 2018, all of them occuring in the MLB Regular Season. In 2018, he relied primarily on his Fourseam Fastball (92mph) and Slider (80mph), also mixing in a Change (84mph) and Curve (73mph). He also rarely threw a Sinker (93mph).
Basic description of 2018 pitches compared to other RHP:
His fourseam fastball has much less armside movement than typical and has essentially average velo. His slider has short glove-side cut and has below average velo. His change generates fewer whiffs/swing compared to other pitchers' changeups. His curve comes in below hitting speed, results in somewhat more flyballs compared to other pitchers' curves and has slight glove-side movement. His sinker (take this with a grain of salt because he's only thrown 3 of them in 2018) is basically never swung at and missed compared to other pitchers' sinkers, is an extreme flyball pitch compared to other pitchers' sinkers, has little sinking action compared to a true sinker and has slightly above average velo.