We are using the following fonts in our maps: Noto Sans, bold and regular and Sorts Mill Goudy Italic. They are licensed under the Open Font License, so there are no restrictions on their usage.
Install these fonts, open up Photoshop and add your own labels to the map! The font settings in Photoshop of most labels are: Size 40px, Tracking (distance between characters) 75, Anti-aliasing: Crisp. And font effects: Stroke 4px white, Opacity 80%.