i second mc mastercarr.
i tried to search the regular socket head but could not find a fully threaded, they all have a shank. however, i did find two fully threaded version. but they're button head and flat head.
this is the button head
3.99 for a pack of 25 screws
this is the flat head, its the kind that you might recognize as countersunk screw.
$10.53 for a pack of 25
they both uses 2mm hex driver. if you are comfortable at using 2mm hex driver at this thread size. personally i'd prefer at least 2.5mm hex driver for any 3mm screws as i feel it's more comfortable to torque the screws.
i think 2.5mm hex driver head are available in regular head.
below are pictures of 3x10mm screws. the regular head has a 2.5mm socket head driver and the button head has a 2mm socket head driver.