ম্যাটপ্লটলিব Cursor

import matplotlib.pyplot as plt
from matplotlib.widgets import Cursor

figure, axes = plt.subplots()

axes.plot(
    [1, 2, 3, 4],
    [2, 5, 3, 8]
)

cursor = Cursor(
    axes,
    useblit=True,
    color="red"
)

plt.show()