This is more for me to keep track of ways to work with Logic Apps & Flow. I will be updating this as I go.

Dates

Daniel over at o365Dude.com has some good information on basic date operations.

Converting Dates from UTC

convertFromUtc(utcNow(),'AUS Eastern Standard Time','yyyy-MM-dd')

Getting the Days between 2 dates

I found this in the answer from leyburn19 on the Power Users forum
div(sub(ticks(convertFromUtc(utcNow(),'AUS Eastern Standard Time', 'yyyy-MM-dd')),ticks(convertFromUtc(variables('FromDate'),'AUS Eastern Standard Time', 'yyyy-MM-dd'))),864000000000)

Adding Days to Dates

addDays(utcNow(),1,'yyyy-MM-dd')

Get the Day of The Week

dayOfWeek(convertFromUtc(utcNow(),'AUS Eastern Standard Time', 'yyyy-MM-dd'))