My first choice for partnering with a purple cardigan would be a grey. However, depending on the shade of purple, you could also use a navy. White and black are also safe choices, but again, it depends on the shade of purple.
purple goes best
The best accent color for red and purple is blue!
Blue , I Think
red....... then it would make purple
purple or royal blue
golden yellow
Any color, depends what kind of pants your wearing.
Pink or Purple
purple
grape purple.
Purple of course! :P
A neon color, or purple