All black holes are not similar.

 All black holes are not similar. 

Which ones came first: stars or black holes? That is one of the key questions in cosmology. Black holes are the most massive and dominating objects in the universe. There is the possibility that some of those black holes could form before the universe. 

Material can form black holes. But before we will go to think why black holes form we must realize that there are different types of black holes. Two of those black holes are confirmed, but nobody has seen the third type yet. 

1) Supermassive black holes

2) Stellar mass black holes

3) Quantum-size black holes. 

The gas cloud that collapses can be too heavy. And that thing can form a black hole or neutron star or even a white dwarf. If a collapsing nebula is too heavy the star's nuclear reactions cannot start because massive gravity turns material into a black hole or neutrons. That thing causes situations in which fusion cannot start. 

It's possible. That supermassive black holes are not forming like stellar mass black holes. The interstellar nebula may collapse because of its internal gravity interaction. In that case, the weight of the collapsing gas nebula is so high, that the star that should ignite its fusion reactions collapses into black holes. That causes another question: could those too-heavy nebulas form things like neutron stars and white dwarfs? 

So when collapsing stars are forming stellar-mass black holes. Quantum black holes are particles that turn so heavy, that they turn into black holes. Electromagnetic radiation like GRBs may turn electrons and other particles in its route into the black hole. Is possible to turn electrons into quantum-size black holes by stressing them with laser rays. Those quantum-size black holes can turn into superposition and entanglement. They offer one possibility to create static quantum entanglement. 

Wave-particle duality means that a black hole can form straight from wave movement. Or wave-particle duality forms the particle cloud that collapses forming a black hole. 

Wave-particle duality means that wave movement can transform into particles. And particles can transform into wave movement. So that means the wave-particle duality can make the black hole straight from wave movement. When two quantum fields impact each other they form particles. Those particles can form particle clouds that can collapse and form black holes. 

But then to the hypothesis that there were black holes before the universe was born in the Big Bang. The wave-particle duality can explain that thing. The radiation or wave movement has mass like all other particles except photons. 

The thing is that the spin of a photon is -1 or +1. That can make it possible for photons can just flow in their quantum field. And because there is energy stability in that particle where the photon gets the same energy mass as it delivers. It's hard to measure the photon's mass.

Wave-particle duality means that wave movement can turn to particles. And in some versions, the impacting quantum fields in the young universe formed black holes. When those wave movements or radiation impulses hit each other, they form a particle group. Then the internal gravity collapses that form. That thing can form a black hole straight from radiation. 

https://en.wikipedia.org/wiki/Wave%E2%80%93particle_duality