Export Raster Attribute Table using Open Source software

I’ve got 120 or so geotiff files that I’d like to build and export the raster attribute table to something a little more friendly (e.g. csv).

I’m curious if there is an open source way to do this. The files are rather large 36001 X 36001 pixels so brute force solutions may be out. Ideally, I’m looking to do this in gdal commandline/OSGEO4w or Qgis. Grass in a pinch.

Thanks!