If your profile picture seems like it needs more flair, than you should consider equipping a frame! Frames are visual borders that are displayed around your profile picture that your opponents can see. You might want to equip a frame because you like how it looks, or to show off a frame which is rare and difficult to get.
Frames can be earned by completing World Tour collections or Social Goals. You can check out your current frame collection by tapping your player profile on the World Map or the Settings menu in the upper right.