Usually, horizontal lines are added to a chart to highlight a target, threshold, limits, base, average, or benchmark. These lines, for example, can help control if a process is behaving differently than usual. Excel allows you to add a vertical line to an existing chart in several different ways, e.g., by calculating line values for a scatter, line, or column chart, but using error bars is the easiest way to add a vertical line to a chart:

The waterfall chart, also known as the cascade or bridge chart, shows the positive or negative change of the initial value under the influence of various factors, such as time. The main purpose of this chart is to show the viewer how the value has increased or decreased over a certain period or under the influence of certain factors:

Vertical lines are usually added to the chart to highlight the current date, a critical date, or a deadline. There are many ways to add a vertical line to the existing chart. Errors bars are the easiest way to add a vertical line to a scatter plot. See how to add a vertical line to a line or bar chart or a horizontal line to a scatter plot, line, or column chart:

Sometimes you can give your charts a more impressive view by showing deviations of some real process from its expected flow.

A bullet graph (the name by its inventor Stephen Few) or bullet chart (in Microsoft office) generally is used to display progress towards the specific target:

To show progress, highlight current or any date, or demonstrate the difference between the target value and the actual one, you can add bullets to the chart, horizontal or vertical lines:

Surveys are used to collect opinions, preferences, and choices of the target audiences. They can be used to provide information that will help to make better business decisions. Surveys can help forecast demand and help businesses better prepare for the future.

A bidirectional chart, also known as a two-sided bar chart, is used to compare two (rarely more) sets of data side by side along the horizontal axis. Unlike other similar charts, such as the divergent chart (butterfly, mirror, tornado, etc.) and the Likert scale chart, the bidirectional histogram bars start on opposite sides and are directed toward each other.

It is often necessary to visualize the results of voting or polls in which the answers belong to different scales. For example, when collecting data on preferences, such as choosing from the proposed persons, teams (parties); applications, browsers; gadget models; food, colors; etc. See how to organize a team color preferences survey in Outlook.

The tornado chart is a modified version of bar charts with two columns of data series whose bars are horizontal and pointing in opposite directions, with the base in the middle of the chart. In fact, the only difference between the tornado chart and the very similar charts - the butterfly chart and the mirror chart - is that the data series used to create the tornado chart must be sorted from the largest to the smallest.