Hi Sperry;

I am not sure of which brands at the moment, but I found some of the 9 and 6 volt batteries were just smaller batteries bundled in the case.
I opened one dead 9 volt out of curiosity once and found it was full of LR44 size button cells. Not all of them are like that though.
I am sure there is a list somewhere detailing what is in which cases. It might be handy to know.

I use rechargeable batteries for all the standard sizes.
Newer rechargeables like nickel metal hydrides perform quite well