  We discuss the goals, the designs, the state of technical readiness, and the
critical R&D needs of the accelerators that are currently under discussion as
Higgs and electroweak factories. We also address the respective staging options
enabling future energy-frontier colliders. The accelerators covered are based
on many different techniques and approaches. They include several circular
colliders, various linear colliders, colliders based on energy recovery linacs
(ERLs), ERL-ring combinations, as well as gamma-gamma colliders. The linear
colliders proposed consist of options for the International Linear Collider
(ILC), for the Compact Linear Collider (CLIC), for the Cold Copper Collider
(C^3), and for the more recent Higgs-Energy Lepton Collider (HELEN). ERLs are
key components of the Recycling Linear e+e- Collider (ReLiC), of the Energy
Recovery Linear Collider (ERLC), and of the Circular Energy Recovery Collider
(CERC). Among the more conventional ring colliders, the following proposals are
featured: the Future Circular Collider (FCC-ee), the Circular Electron Positron
Collider (CEPC), the Electron Positron Circular Collider at Fermilab (EPCCF),
and the Large Electron Positron collider $\#$3 (LEP-3). In addition, we
consider the X-ray FEL based gamma-gamma Collider Higgs Factory (XCC) and the
High-Energy High-Luminosity gamma-gamma collider (HE&HL gamma-gamma). Finally,
a Higgs factory based on a circular muon collider is mentioned for
completeness.
