PLA

PLA's roots are 19th-century chemistry — low-molecular-weight PLA was first made by Théophile-Jules Pelouze in 1845 — but it stayed a lab curiosity for over a century, until biomedical engineers adopted it for resorbable sutures and Cargill industrialized corn-derived PLA in the 1990s.

In FDM it became the default beginner material: the RepRap movement printed on unheated beds, and PLA's low warp and low print temperature made it the most forgiving choice. It remains the most-printed filament on Earth.