Preparations are well underway for Roman, Rubin, and Euclid to carry out ambitious imaging and spectroscopic surveys that will enable leaps in our understanding of cosmology and a wide range of astrophysics. Simulated data, both mock galaxy catalogs and simulated images, will play critical roles in survey planning, analysis, and ultimately, the science output from these missions. In this talk, I will discuss the potential scientific impact of providing user-friendly public access to simulated data sets. I will focus on a NASA-supported project to provide such access to a selected sample of simulated catalogs and images. Finally, I will discuss the challenges and next steps required to support the science goals of these missions with a mature archive for simulated data sets.