In the past I was working on different plugins to connect with multiple APIs and use their isochrone endpoints in QGIS. Let me summarize some of my findings and share my opinion on HERE, Azure Maps, Bing Maps, ORS, Esri and Iso4App.
Two years ago I wrote the OSMroute plugin which enable the QGIS user to use the OpenRouteService API for geocoding of points, accessibility analysis as well as routing from A to B. Unfortunately the managing of a plugin/ open source tool is time-consuming/ hard. But fortunately Nils Rode lifted the plugin to a new level: OSM tools.