"Stronger than Wonder Woman" was her only power. She was also willing to work with Wondie's 95% Nazi classic Rogues Gallery so there's that.
When shit rebooted for the silver age she became a scientist who switched brains with a gorilla who yadda yadda convoluted bullshit, can change size.
Later on she became a sexually independant woman character, basically villain She Hulk.
Since Timm redefined the DC universe for a generation, his version which is based on all three Gigantas became the norm.