i just upgraded to Kodi 18 release build from the last stable version. Until now everything works fine, but under My Add-ons/Game Add-ons the emulators section is completely missing. The only game addon which is preinstalled is the 2046 game.
According to that thread, all emulators should be preinstalled: Kodi 18 missing "emulators" section in "Game Addons"