For the hover indicator (the border, that is blue by default, that appears when you move the mouse cursor on a button) Oxygen has a nice fading effect, so that buttons seem to glow when you hover them.
We now have this subtle effect also in Joxy for JButtons and JToggleButtons. The other components whose KDE counterparts have the glowing effect, such as the JComboBox and the JRadioButton, will get animations in Joxy soon.
By the way, we also have (since a week) nice KDE-like tooltips in Joxy.