Neither the An-14 nor the AN-28/M-28 has a ramp, though both have longitudinally-hinged ventral doors.
And strictly speaking, the Skyvan doesn't have one either, at least not an integral one that can be lowered for loading as per, say, the C-130 or C-17.
I agree with the previous posters, the Ahrens and CASA are the only examples I can think of.