Cycle through color schemes with Next in cycle (Ctrl-M) and Previous in cycle (Ctrl-Shift-M).
Set which color schemes are in the cycle with Add current to cycle and Remove current from cycle. You can also manually edit the
cycled_color_schemes preference. For example, putting this in your settings file lets you toggle between Solarized light and dark:
"cycled_color_schemes": [ "Packages/Color Scheme - Default/Solarized (Light).tmTheme", "Packages/Color Scheme - Default/Solarized (Dark).tmTheme" ],