Our stock library has an icon for every occasion. Choose icons that are already coloured, or choose a white or dark icon, and then choose a background for your icon in your theme's colours.
For example, add an icon to your content object in Layout View:
Choose an icon from the stock library:
Use the Asset editing toolbar to change the background colour, size, placement etc of the icon.
Design Tip: Use icons consistently throughout your learning experience. Choose icons in the same style (all stock icons are categorised by style) and use colours from your theme.