My group recently migrated from classic to New Google Sites. There were many things I was doing with classic sites and/or apps script's Sites Service I can't do
csrf-protection
badgerdb
distortion
mule4
bigbluebutton
splunk-formula
geonames
uikit-state-preservation
gcovr
osgi-fragment
razzle
redmine-plugins
mod-ssl
2048
stack-frame
youtube-javascript-api
enroute
swiftui-view
app-globalresources
asp.net-core-1.1
amz-sp-api
azure-webjobs-triggered
flexdashboard
createtextnode
openfaas
visual-studio-package
no-www
conversion-tracking
postmates
gobblin