Question: 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!

Answer: 
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.*