Higgsless model
In theoretical physics, one promising candidate for a united field theory is Heim Theory, a quantum gravitational approach which achieves a description of the forces in an extended 8 dimensional theory. It predicts the particle masses without using the Higgs boson.
The basic theory, put forward by Burkhard Heim, is 6-dimensional, which is sufficient for derivation of the particle masses using the Higgsless mass formula. The extension to 8 dimensions by Walter Droescher, in association with Heim, puts in the interaction picture, which involves metrons, elementary surface elements analogous to branes in string theory. Inertia arises naturally as a result of the metron interactions, without need of a Higgs boson.
For a detailed description of how accurate values for the particle masses are derived within Heim Theory, see [1].