The marker "d" is a skewed version of a diamond, "D". You may create such diamond marker and skew it in the other direction.

For arbitrary angles, you may rotate the marker instead.

import matplotlib.pyplot as plt
from matplotlib.markers import MarkerStyle

fig, ax = plt.subplots()

plt.scatter([1,2,3],[1,2,3], s=225, marker="d")

m = MarkerStyle("D")
m._transform.scale(1.0, 0.6)

plt.scatter([1,2,3],[2,3,4], s=225, marker=m, color="crimson")

m = MarkerStyle("d")
m._transform.rotate_deg(60)

plt.scatter([1,2,3],[3,4,5], s=225, marker=m, color="limegreen")

plt.margins(0.5)
plt.show()