There is literally no need for 512x512 textures for arrow buttons that are basically 64x64 in size. Reduce all textures to 256x256 and 128x128 for smaller buttons or similar. The textures such as the robots should be 256x256 as they are only 1x1 in size; vanilla expanded itself uses 512x512 for 2x2 royal beds, so 256x256 should be a better fit for RAM usage.