I like
Martha, there's just something so sweet, chipper, and innocent about it.
I prefer
Martha Jane to
Martha Caroline.
Martha Jane has a nice touch of vintage spunk.
I have
Martha "
Marty"
Avalon on my old name list, back when I thought
Avalon was the bee's knees but afraid that it might be tacky/trendy in the first spot. I think
Martha Nikolett or
Martha Evelina could be nice. I also really like
Martha Rose, despite
Rose being sort of "filler."