These are not suggestions for you but how I make dresses "versatile"
Palava - all of their dresses are cotton, linen or tencel. The cotton and linen are heavier weight anyway. In autumn / winter I wear the darker coloured dresses with a thin long sleeved thermal vest and a waist slip, with chunky cardigans, probably Palava heritage range or Fair Isle, waist length, not long on top and thick opaque tights and flat boots.
Palava
Oska, same principle but with Oska boiled wool jackets/ cardigans, which might be long.
Oska.
with both I'd wear indoor scarves, silk, wool, cotton and fingerless gloves if really cold.
Toast
I don't have anything from Toast but this would work with Toast as well.
Toast
This could be also done with Nobody's Child, Joannie and Seasalt. It's also completely do'able with expensive upmarket brands like Apuntob, Album Di Famiglia, Girls of Dust, Casey Casey (the latter mostly being hated on here but they are versatile)