Line Chart
Line charts are the go to for date and time for a few reasons:
1. date and time are continuous - meaning there exists values between the times when data is collected, so the connecting lines can indicate where those hypothetical values might fall.
2. Generally, people perceive the passage of time in the direction that you read and write. So if you read and write in English, then you likely perceive time as passing from left to right, which is visually represented in a line chart.
Use color and a legend to add another variable/ dimension to a line chart!
Dumbbell Chart
Dumbbell charts are good for showing the start and end time (or date) of different categories.
Timeline
Timeline's are good for naretive data - If the date or time is associated with significant qualitative data.
Nightingale Rose Chart
Circle visualizations like the example can be used to represent circular values like 24hours or a year. This does not work for a full date value (e.g. January 1, 1999) as year is not circular.
One downside to this chart is that it is harder to compare across the circle; for example, in this image it is difficult to tell the difference between the values in Feb and Jul as they are similar in size but far apart on the graph.
Theses visualizations have many different names: Nightingale rose chart, polar area chart, coxcomb chart, aster plot