Might’ve been MonoGame? It sounds enough like Godot that you might’ve confused the two, it’s a code-first framework, and it’s popular enough that you might’ve heard of it (Stardew Valley, Bastion, and Celeste are all built on MonoGame)

I would bet SDL; it's a C library that a ton of other libraries are influenced by or based on. It's not usually thought of as an engine on its own nowadays

LibGDX?