One of the reasons to use Leaflet as your JavaScript mapping API is the large number of basemaps available.
This includes very useful basemaps, showing streets, topography, cities, borders, aerial imagery, etc. that you can overlay your data on.
There are also a number of fun and artistic basemaps available, such as the heavy metal themed Spinal Map, artistic water color maps, old-timey pioneer themed maps, and others.
You can see a live version of about 20 of these basemaps at https://millermountain.com/basemap/.