I've installed QGIS 3 today. I found the xyz tiles option and have added e.g. google, openstreet, and ESRI Topo. These all work and show the map. Now I'm looking for a topo map, so ESRI topo is a nice starting point. Unfortunately I find it a bit blurry on the font, and the lines a bit to light.
Does someone know working XYZ topo entries? I can find some XYZ tile servers for topo, but they are often not downloading tiles