If you are on the look for an aesthetic worldwide topographic map (with contour lines, …) OpenTopoMap is worth a “visit” (https://opentopomap.org). With “XYZ-Connections” it is also a quite usefull basemap within QGIS projects.

OpenTopoMap is a topographic map out of data from OpenStreetMap and SRTM (see https://github.com/der-stefan/OpenTopoMap).

How to use it in QGIS:

• Open the Data Source Manager
• Add a new XYZ-Connection
• The recent URL for the tiles is: https://tile.opentopomap.org/{z}/{x}/{y}.png