Source code in 15 libraries — Python: Altair, Bokeh, lets-plot, Matplotlib, Plotly, plotnine, Pygal, Seaborn; R: ggplot2; Julia: Makie.jl; JavaScript: Chart.js, D3.js, Apache ECharts, Highcharts, MUI X Charts.
A line plot with the area between the line and the baseline (typically x-axis) filled with a semi-transparent color. This creates an area chart effect for a single series, emphasizing the magnitude of values.

Preview render from the D3.js implementation.