  I present several scenarios developed in Zagreb, in which TeV-scale particles
belonging to non-trivial weak-isospin multiplets give rise to neutrino-mass
mechanisms different from conventional type I, II and III seesaw models. Two
dim 9 tree-level mechanisms, presented first, provide an appealing testability
of their exotic TeV-scale particles at the LHC. These models are not genuine,
since their particles also provide competing dim 5 loop contributions. The
loop-models presented next are genuine, without competing tree-level
contributions. Among them, the three-loop model involves high-order weak
multiplets leading to Landau poles. The one-loop model with scalar triplet as
the largest multiplet, in addition to good UV properties, provides the particle
set promising for gauge coupling unification. Therefore, it served us as a
starting point for a study of SU(5) embedding of additional particles leading
to viable unification scenarios. To distinguish among them begs for additional
principle which reigns over particle completion and eventual dark matter
considerations.
