Assuming making your own isn't an option (it's not hard, just fill a jamjar 1/3 with cream, shake till it resembles scrambled eggs and clears the glass, strain, wash and pat), one that we like when we have to buy some is Delamare's Goat Butter. It doesn't taste in the slightest bit goaty, and of all the butters we've tried, it's our favourite shop-bought one.