It is hard to find a generic presentation slide template that shows a "trend". In principle, any data chart can do the track. Here are a few of the basics.

 
Column charts compare things over time (as opposed to bar charts that rank items)

Column charts compare things over time (as opposed to bar charts that rank items)

You can add more data series to a column chart, the less important one goes in the "bubbles" under the year labels

You can add more data series to a column chart, the less important one goes in the "bubbles" under the year labels

Add more than one column chart on a slide to show 2 variables over time

Add more than one column chart on a slide to show 2 variables over time

A simple "from to" diagram to show a trend without the need for quantitative information

A simple "from to" diagram to show a trend without the need for quantitative information