You can add one of over 400 icons to your block titles to help them stand out to your visitors.
1
Edit the Block
Click on the gear icon in the top right of the block your want to add a block icon title to and Select 'Edit Block'.
2
Scroll down until you see the Block Icon Title section and click the link to open up the section.
Click the radial button next to the icon you want to use for the block title.
Click 'Save'.