I want to make pixel art in Gimp, but the grid that I pull up is only a filter. I'd like to get a perfect fill for each pixel instead of having to measure the pixel and line it up each time. Is it possible to get a grid that can do this? Thanks!
No grid is needed, use real pixels for pixel art. Define your new image for example to be 60 pixel wide and 40 pixel high. Then draw with 1 pixel wide pencil.
If you want a copy with higher pixel dimensions, make a copy and scale it (Image > Scale). Define interpolation method = None to keep it sharp
Image → Configure Grid... and View → Show grid or View → Snap to grid.