This 4-pack from Master Lock has never let me down: https://www.amazon.com/gp/product/B00004Y8CQ
Master Lock makes a good small padlock. You can get them on Amazon Master Lock Padlock, Solid Brass Lock, 3/4 in. Wide, 120Q (Pack of 4-Keyed Alike) https://smile.amazon.com/dp/B00004Y8CQ/ref=cm_sw_r_cp_apa_i_wRRcCbYQ004YD