Annuals in containers will all need deadheading to prolong flowering - it depends what you mean by low maintenance. I think closely planted pelargoniums are as trouble free as any as they withstand dry compost better than most if you forget to water them. Even they look a lot better for having the dead flower heads removed though. Unfortunately you can't just plant and ignore any of them!

Tuberous begonias, fiberous rooted begonias and Geraniums.

They hardly need dead heading, tolerate dry and look damn good.

They do require watering and feeding if they're to look good

I forgot begonias - yes definitely.

I have taken to osteospermum, more a short lived perennial, but lovely colours and very easy. One fills a pot.
I take them in the gh overwinter and in mild years with a trim last a few years.

I grow begonia sempervirens in summer and winter flowering pansies in Winter. Neither need much attention. Make sure your pansies are flowering stage when you plant them for the winter. Only necessary to dead head if the plant tries to produce seed heads. if you allow those to develop the plant will stop producing flowers and favour producing the seed heads instead. As the weather gets cooler the plant gives up on trying to produce seeds and will happily give you flowers all winter. The begonia sempervirens has the added advantage of being very drought tolerant. No need to worry about watering when you go on holiday.