  Surface plasmons, which allow extreme confinement of light, suffer from high
intrinsic electronic losses. It has been shown that stimulated emission of
electrons can transfer energy to plasmons and compensate for the high intrinsic
losses. To-date, these realizations have relied on introducing an external gain
media coupled to the surface plasmon. Here, we propose that plasmons in
two-dimensional materials with closely located electron and hole Fermi pockets
can experience gain, when an electrical current bias is applied along the
displaced electron-hole pockets, without the need for an external gain media.
As a prototypical example, we consider WTe$_2$ from the family of 1T$'$-MX$_2$
materials, whose electronic structure can be described within a type-II tilted
massive Dirac model. We find that the nonlocal plasmonic response experiences
prominent gain for experimentally accessible currents on the order of
mA$\mu$m$^{-1}$. Furthermore, the group velocity of the plasmon found from the
isofrequency curves imply that the amplified plasmons are highly collimated
along a direction perpendicular to the Dirac node tilt when the electrical
current is applied along it.
