What you're probably looking for is a circular fisheye lens for APS-C. Fisheye lenses come in one of two types: circular or diagonal. Circular ones put the entire image circle inside the frame of the sensor, while diagonal ones are more traditional and project an image circle large enough to cover the entire sensor and yield a rectangular image.

Keep in mind, however, that with a circular fisheye, you get a lot of black on the frame along with the image circle, so you are effectively reducing the resolution of your camera, and that with a more extreme circular fisheye, you may be trading in sharpness and chromatic aberration for the additional scene coverage, vs. a diagonal.

Most circular fisheye lenses can do 180º across both the short and long edges of the frame, but most diagonals only achieve 180º scene coverage across the diagonal (e.g., Samyang/Rokinon 8mm f/3.5 diagonal fisheye for APS-C).

Some circular fisheyes for crop include:

• Sigma 4.5mm f/2.8
• Lensbaby 5.8 f/3.5
• Meike 6.5 f/2 (rebranded as Opteka 6.5 circular sometimes)
• Yasuhara/Madoka 180 7.3mm f/4 (for mirrorless, Sony E/Fuji X)

And I even found one for MFT:

• Laowa 4mm f/2.8

So, probably digging about for Asian-made manual lenses might yield a few more candidates.