柱状图阴影

Python
hatches = ["/", "\\", "|", "-", "+", "x", "o", "O", ".", "*"]
# * 表现为星星
bars = plt.bar(x, y, bar_width, hatch=...)

参考：https://matplotlib.org/stable/gallery/shapes_and_collections/hatch_style_reference.html

折线图填充

Python
plt.fill_between(x, y_bottom, y_top)

会在 y_bottom 到 y_top 之间填充颜色。
示例（紫色区域）： Fill between example

柱状图标注数值

Python
from matplotlib.axes import Axes
def add_num_annotation(ax: Axes, acc=2, rotation=0, margin_bottom=2, fontsize=18):
    for _p in ax.patches:
        if _p.get_height() == 0:
            continue
        ax.annotate(
            str(round(_p.get_height(), acc)) if acc != 0 else str(int(round(_p.get_height(), 0))),
            (_p.get_x() + _p.get_width() / 2.0, _p.get_height() * 1 + margin_bottom),
            ha="center",
            va="center",
            xytext=(0, 6),
            textcoords="offset points",
            rotation=rotation,
            fontsize=fontsize,
        )

Acknowledgement: Chengzhi Lu.