Not to be pedantic but the "dedicated" circuit for a fridge is 15a, otherwise it can be on a SA circuit.
That is also true of the microwave (SA circuit) if it is not permanently mounted.
I doubt many actually pull much more than a toaster anyway.
The 2 SA circuits in my kitchen that I pulled make me legal but there are also 3 15a circuits that were existing and have other outlets. In 1963 I doubt they had a code issue with that.
I am still not sure I have them all mapped but I know one is shared with the bathroom light on the opposite wall. It was also feeding the counter but I fixed that very early in my residence here because hair dryers were taking out the fridge. Now it is just the vanity light, fridge and a battery emergency light charger in the hall.
