This data set contains viscosity measurements for hydrogen and for mixtures containing hydrogen and components relevant for blue-hydrogen production. Measurements were carried out with highly accurate gas-phase viscometers utilizing magnetic-suspension technology. Results are published in Betken, Benjamin; Khosravi, Bahareh; Sabozin, Fabian; Thol, Monika; Span, Roland; ,"Measurements of the Viscosity of n-Hydrogen and (n-Hydrogen+ Carbon Dioxide),(n-Hydrogen+ Methane), and (n-Hydrogen+ Ethane) Mixtures at Temperatures from (253.15 to 473.15) K and at Pressures up to 20 MPa",International Journal of Thermophysics,46,4,55,2025,Springer US New York