  Materials with tunable topological features, simple crystal structure and
flexible synthesis, are in extraordinary demand towards technological
exploitation of unique properties of topological nodal points. The controlled
design of the lattice geometry of light elements is determined by utilizing
density functional theory and the effective Hamiltonian model together with the
symmetry analysis. This provides an intriguing venue for reasonably achieving
various distinct types of novel fermions. We, therefore, show that a nodal line
(type-I and II), Dirac fermion, and triple point (TP) fermionic excitation can
potentially appear as a direct result of a band inversion in group-I nitrides
with $\alpha$-Li$_{\rm 3}$N-type crystal structure. The imposed strain is
exclusively significant for these compounds, and it invariably leads to the
considerable modification of the nodal line type. Most importantly, a type-II
nodal loop can be realized in the system under strain. These unique
characteristics make $\alpha$-Li$_{\rm 3} $N-type crystal structure an ideal
playground to achieve various types of novel fermions well-suited for
technological applications.
