Always check the R-squared value and the residuals plot after performing a fit. A high R-squared is good, but randomly distributed residuals are the true sign of a mathematically sound model.

A KDE-based project, LabPlot provides an easy way to create, manage, and edit plots. It allows for advanced curve fitting directly from spreadsheets.

Automated plotting and users comfortable with a CLI.

Automatic ranking of fits based on statistical error. 5. LabPlot

Support for LaTeX formatting in graphs and integrated analysis toolboxes. How to Choose the Right Tool?

Linux users and those who prefer a modern, polished interface.

SciDAVis is a cross-platform application for interactive graphing and data analysis. It is often cited as the best free alternative to Origin.