  The exotic decay modes of non-Standard Model Higgses can serve as powerful
search channels to explore the parameter space of extended Higgs sectors. In
this Snowmass contribution, we illustrate this using the Two-Higgs Doublet
Model (2HDM) as an example. We first review the current experimental
constraints on the parameter space of a Type-II 2HDM arising from existing
searches for the exotic Higgs decay mode $A/H\rightarrow HZ/AZ$. We then
present the sensitivity of future colliders to discover addition Higgs bosons
using the exotic decay channels $A\rightarrow HZ$, $A\rightarrow H^\pm W^\mp$
and $H^\pm\rightarrow H W^\pm$. We find that a 100 TeV collider can probe
almost the entire region of the Type-II 2HDM parameter space that survives
current theoretical and experimental constraints and would therefore be an
ideal machine to search for heavier Higgses in hierarchical scalar sectors.
