String Theory constructions, in our current understanding, feature large number of additional scalar fields, aka moduli fields. Although these moduli are typically very weakly coupled (gravitational) to the Standard Model degrees of freedom, they can play a significant role in the early universe, potentially leading to observational consequences. In this talk I will present several examples where signatures from moduli dynamics in the post-inflationary universe can emerge. This includes the formation of oscillons, star-like and solitonic objects, and phase transitions in the moduli sector. This talk is based on 1708.08922, 1806.04690, and 1607.06813.