Gnuplot is the best plotting interface I’ve ever used. Once you’ve learned “the Gnuplot language”, it’s very fast and efficient to visualize anything and iterate on it interactively, and I personally find it more usable than GGPlot, Matplotlib, Seaborn, Bokeh, and Matlab.
I think Gnuplot is undervalued because by default the results look horrible. Like many power tools, it requires some config in ~/.gnuplotrc to modernize the looks; http://gnuplotting.org/ is a great source to get started.
Unfortunately, I’m mostly using Matplotlib these days because the data generation is in Python. But despite using it on and off for over a decade, I’m nowhere near my efficiency in Gnuplot, and often have to ask Google or Copilot for help if I’m doing something more complex.