Why do we say that there are different kinds of electrons when discussing different situations in physics? For instance the Weyl electron, Dirac electron etc. From my exceedingly basic knowledge isn't it a basic result of quantum mechanics that particles are indistinguishable? In solid state physics lecture courses I have had, we have always just said "electron" when talking about semiconductors and metals etc.
They are all identical electrons. Its just that for the purpose of the paper or whatever they are behaving according to the rules of Dirac's equation, etc, because of the circumstances the electron is in. 'Free electron' means an electron flying about on its own, while a bound electron is in an atom and a Dirac electron is one that needs to be modelled using Dirac's equation: http://spinograph.org/blog/what-heck-dirac-electron