Galleries are a fundamental building block for PowerApps. One of the most untuitive things to do is pointing at a gallery item with the mouse. However nothing happens, the background of the item is not highlighted, the colors of the item doesn't change,... so you really have to look very good where the mousepointer is to know where you're at.
There is however a native property for table items "HoverColor" and "HoverFill" that could fill this gap in the gallery experience. Could you please add these properties to the gallery so we can create a more user friendly and interactive experience?