Abstract: Accurate mass measurements for supermassive black holes (SMBHs) are critical for understanding their evolution over cosmic time and their co-evolution with their host galaxies. Outside of the local Universe, reverberation mapping (RM) of active galactic nuclei (AGN) is the most accurate method for measuring SMBH masses. RM measures the time lag between the continuum and broad emission line region (BLR) variability of AGN, which gives the virial mass when combined with the broad line width. I will present the latest results from the Dark Energy Survey (DES) - Australian DES (OzDES) RM project, which monitored 735 AGN for 6 years with weekly photometry and monthly spectroscopy. Our results include some of the highest-quality Mg II lags and a new relationship between the radius of the Mg II BLR and the continuum luminosity (R-L relation). The Mg II R-L relation is extremely important because it is widely used to estimate the masses for large numbers of SMBHs from single-epoch spectra and study the SMBH demographics at cosmic noon – the peak of AGN activity. I will also present AGN accretion disk size measurements from continuum RM, and simulations of the survey strategy of future RM campaigns to maximize the scientific yields.