Two ginger nut biscuits after milking. I've started bringing my in-kid goat in to stand on the milking bench. It's seven months since I last milked her but, before she'd get down, she looked at the biscuit tin expectantly.
I did have a goat who loved salted peanuts.
Apple, banana, any fruit really. Biscuits, bread, carrot, but mostly they have horse treats.