  A composite Higgs boson is likely to be accompanied by additional light
states generated by the same dynamics. This expectation is substantiated when
realising the composite Higgs mechanism by an underlying gauge theory. We
review the dynamics of such objects, which may well be the first sign of
compositeness at colliders. We also update our previous analysis of the bounds
from LHC searches to the latest results, and discuss the projected reach of the
High-Luminosity run.
