Simple graph types include line charts, area charts, column charts, bar charts, segmented bar/column charts, pie charts, and doughnut charts. Line charts show changes over time and compare variables. Area charts show changes in volume over time. Column charts compare data at specific times or between nominal categories. Bar charts emphasize comparisons. Segmented charts show proportional relationships and sub-elements over time. Pie charts compare parts to a whole. Doughnut charts are like pie charts but can show multiple data series.