Satellite missions like GRACE (now followed by GRACE-FO) and GOCE have remarkably advanced our knowledge on the global Earth’s gravity field, by measuring the first and second derivatives of the gravitational potential. However, a more precise gravity field model with better spatial and temporal resolution is still highly required by various geoscience disciplines such as oceanography, solid Earth physics, geodesy, etc. New technologies based on quantum optics emerged and quickly developed in the past years. They will enable novel observation concepts and deliver gravimetric observations with an unprecedented accuracy level in future. For the first time, optical clocks provide the particular opportunity to directly observe gravity potential differences through measuring the relativistic redshift between clocks connected by dedicated links (“relativistic geodesy”). Moreover, cold atom interferometry and optical gradiometers have extensively been studied. They will potentially provide gravity gradient measurements with an accuracy of about one order of magnitude better than the electrostatic gradiometer that was used in GOCE. To figure out how these future gravimetric observations may benefit the modelling of the Earth’s gravity field, we ran simulations using multi-source data, including gravity gradients, gravity accelerations and (satellite-based) clock measurements. Estimated instrument errors are mapped to the gravity field coefficients. Additionally, the individual contribution of each type of the new observations is evaluated, including its spectral behavior. Our results indicate that resulting gravity field solutions might be one order of magnitude more accurate than the current satellite-only models.