lxrandr

LXRandR is the standard screen manager of LXDE. It manages screen resolution and external monitors.

Glxinfo

glxinfo is a command-line tool that can help you diagnose problems with your 3D acceleration setup.

GUI tools for diagnosing, repairing, and failsafing X.org issues.

ARandR is designed to provide a simple visual front end for XRandR.

cpuid dumps detailed information about the CPU(s) gathered from the CPUID instruction, and also…

DRIconf is a configuration applet for the Direct Rendering Infrastructure.

feh is an X11 image viewer aimed mostly at console users.

read-edid is a pair of tools (originally by John Fremlin) for reading the EDID from a monitor.