Where are the Plugins for Downloading OSM-Data and the Openlayer-Plugin (with MORE than OSM). These are the most-importent plugins for me! Gone? Then I go back to QGIS 2 ;(
All plugins from earlier versions must be updated to be compatible with QGIS 3.0. If your favorite plugins are missing, be patient and wait for the plugin developers to update them. 3.0 hasn't been out very long.
Regarding the openlayers plugin, there's a much better option already updated for QGIS 3.0: QuickMapServices.