  Plasmons of quark-gluon plasma - gluon collective modes - are systematically
studied. The plasma is, in general, non-equilibrium but homogeneous. We
consider anisotropic momentum distributions of plasma constituents which are
obtained from the isotropic one by stretching or squeezing in one direction.
This leads to prolate or oblate distributions, respectively. We study all
possible degrees of one dimensional deformation from the extremely prolate
case, when the momentum distribution is infinitely elongated in one direction,
to the extremely oblate distribution, which is infinitely squeezed in the same
direction. In between these extremes we discuss arbitrarily prolate, weakly
prolate, isotropic, weakly oblate and arbitrarily oblate distributions. For
each case, the number of modes is determined using a Nyquist analysis and the
complete spectrum of plasmons is found analytically if possible, and
numerically when not. Unstable modes are shown to exist in all cases except
that of isotropic plasma. We derive conditions on the wave vectors for the
existence of these instabilities. We also discuss stable modes which are not
limited to small domains of wave vectors and therefore have an important
influence on the system's dynamics.
