It is conjectured that the successive phase transitions (namely, the separations between the initially unified forces) occurred after the Big Bang might have created exotic relics that supposedly would survive until our days, like the monopoles and strange particles.
Features like the monopoles (supermassive points with a single magnetic pole instead of the usual negative and positive poles), cosmic strings (unidimensional lines confining false vacuum (a vacuum full of energy) from the early Universe, endowed with a big quantity of energy and mass (1 metre may match the entire Earth's mass)), dominion walls (bidimensional nets that fragment the Universe in cells and are endowed with anti-gravitational energy) and textures (tridimensional defects that are analogue to the ones previously described) may have been generated by soft or dramatic phase transitions.
According to one hypothesis, the phase transitions would take place through the expansion of "bubbles" of the Universe from the new phase into regions still dominated by the previous phase. According to another hypothesis, the transition would occur in a more gradual and continuous way.
The cosmic strings may, namely, allow a hot dark matter picture, since the excessive homogenization of the Universe created under this scenario is counterbalanced by the huge force that the strings possessed in its early history.
Net of cosmic strings (Allen & EPS)
Other entities that may result from the Big Bang are the neutrinos and the anti-neutrinos (hot dark matter) little interactive with other particles and endowed with an insignificant rest mass. As is said in the previous sub-chapter, would be that small interaction power that would have had prevented them to mutually annihilate and, thus, they would have survived until today in big quantities.
On the other hand, the hypothetical axion is an almost massless particle, which holds a mass that is much lower to the neutrino's and had a low initial velocity being, for that reason, a component of some hypothetical cold dark matter. The observation of an axion would solve the problem of the so-called violation of CP (inexistence of a charge-parity symmetry), which is experienced in some situations.
Other extremely interesting features are the supersymmetric partners. According to this model, the symmetry would expand due to the existence of fermionic counterparts for the bosons (field particles) and bosonic couterparts for the fermions (hadrons and leptons).
This way, as an example, the bosonic counterpart of the electron would be the selectron and the fermionic counterpart of the photon would be the photino, endowed with mass. The existence of supersymmetric partners would eventually be an answer for a large portion of the unobserved matter of the Universe. However, the existence of this kind of particles is also far from being proven.
Some final features deserving an emphasis are the mini-black holes. During the period of very high density after the Big Bang, it's possible that the irregularities and huge pressures provoked the collapse of portions of matter into microscopic black holes, with masses in the range of some billion tons and sizes comparable to an atom's. It wasn't yet discovered any black hole of this kind.