Abstract: The advent of gravitational waves (GW) astronomy opens the possibility of probing experimentally the first second of the universe. As a consequence, having a theoretical control over all the early universe events that may have produced GW signal has become an urgent matter. In this talk we focus on the remnants produced by a first order phase transitions (FOPTs) occurring in the early universe. We will see that, on the top of producing GWs, FOPTs can also produce baryon number and heavy particles within minimal BSM models. We will finally investigate how those different remnants can correlate with signals at GW observers.