Which of the following compounds are paramagnetic in nature?

The molecule is typically paramagnetic if the number of electrons is odd and the electrons are unpaired. The molecule is typically diamagnetic if there are even numbers of electrons and all of them are coupled.

In ${\mathrm{KO}}_2$​,

$19+2*8=35$

There is odd electrons. So paramagnetic.

In ${\mathrm{RbO}}_2$

$37+2*8=43$

There is odd electrons. So paramagnetic.