  We explore generic "unnecessary" quantum critical points with minimal degrees
of freedom. These quantum critical points can be avoided with strong enough
symmetry-allowed deformations of the Hamiltonian, but these deformations are
irrelevant perturbations below certain threshold at the quantum critical point.
These quantum critical points are hence unnecessary, but also unfine-tuned
(generic). The previously known examples of such generic unnecessary quantum
critical points involve at least eight Dirac fermions in both two and three
spatial dimensions. In this work we seek for examples of generic unnecessary
quantum critical points with minimal degrees of freedom. In particular, in
three dimensional space, we identify two examples of such generic unnecessary
quantum critical points. The first example occurs in a $3d$ interacting
topological insulator, and it is described by $two$ $(3+1)d$ massless Dirac
fermions in the infrared limit; the second example occurs in a $3d$ topological
superconductor, and it is formally described only $one$ $(3+1)d$ massless Dirac
fermion.
