Litemeter
Lite damage meter addon that barely uses any CPU.
Icon on minimap to open settings or /lm config.
Can also do /lm to view all commands.
Lock/Unlock button on bottom left of frames.
Resize button on bottom right.
Enjoy!
Also check out Liteplates: https://www.curseforge.com/wow/addons/liteplates
Litemeter Team
