GLXOSD is described as 'On-screen display (OSD)/overlay for OpenGL applications running on Linux with X11. It can show FPS, the temperature of your CPU, and if you have an NVIDIA graphics card (with proprietary drivers), it will also show the temperature of the GPU' and is a system information utility in the os & utilities category. There are eight alternatives to GLXOSD for a variety of platforms, including Windows, Linux, Flathub, Wine and Steam apps. The best GLXOSD alternative is MSI Afterburner, which is free. Other great apps like GLXOSD are Open Hardware Monitor, MangoHUD, Rivatuner Statistics Server (RTSS) and DXVK.