According to MDN, the list attribute can be used for <input> elements of type color to provide a list of predefined colors. That page also indicates that
parameterized-types
x86-64
xorg
material-design-lite
image-loading
biopython
pbrun
eclipse-jee
qt-jambi
relational-algebra
chromebug
scipy-optimize
matplotlib-animation
baud-rate
central-difference
pattern-recognition
swfobject
element
retry-logic
ef-power-tools
guard-statement
odata-connected-service
strict-aliasing
browser-support
docker-selenium
android-4.2-jelly-bean
utf
scala-2.12
php-carbon
eventfilter