In the Free and Vector plan, only vector tiles are available, the raster tiles are in the higher paid plans.
Vector tiles is a modern technology for displaying a map on a web. It is available in all plans, including the Free. It gives end-users better experience zooming and panning because the map is dynamically changing instead of loading a completely new layer with raster tiles. Vector tiles are also smaller and save not only storage space, but also internet traffic. Thanks to the vector technology, it automatically supports any resolution, including HiDPI (retina) displays.
Automatically generated source code for Mapbox GL JS viewer
Raster tiles is a traditional method of displaying a map on a web. Due to the higher requirements for rendering and data storage, it is available for paid customers with higher plans only.
The downside is a size, which is more than 10 times bigger than Leaflet. It is hard for a start but powerful.
While it can do most of the task of OpenLayers, it can lack some of the advanced functionality. However, a lot of functions can be added by third-party plugins.
Automatically generated source code for OpenLayers viewer
Maps generated by MapTiler Desktop
If you have a map in MapTiler Desktop, you have two easy options of how to show it on the web using OpenLayers or Leaflet. Before you start with rendering, you need to select an output format.
MBTiles can be easily uploaded to MapTiler Cloud and served using OpenLayers or Leaflet with above instructions.
If you prefer self-hosting, select Folder option, upload it to your server and open in a browser. There is a simple viewer with a menu on the left: here you can select the Source code for your favorite viewer.