Let's assume that you mean activation patterns at the level of single cells. Aside from the ethical issues which make it virtually impossible to obtain the full set of data, there is also the fact that the exact timing of expression is one of the major ways in which development produces variability in phenotype and so can vary wildly between individuals. The closest we have right now might be HUBMAP [0] or HCA [1], but I don't think that those had as objectives covering multiple developmental timepoints.

0. https://portal.hubmapconsortium.org/ 1. https://data.humancellatlas.org/