The Elder Scrolls Online Collection: High Isle is the ultimate Elder Scrolls experience and includes the Base Game and all Chapters:

Morrowind INCLUDES LATEST CHAPTER: HIGH ISLE—Set out on ESO's year-long adventure, the Legacy of the Bretons, and uncover an epic storytelling experience told across three DLCs and the High Isle Chapter. A tale of chivalric honor and political upheaval set within the stunning Systres Archipelago awaits.ULTIMATE FREEDOM—Create your ultimate RPG character, play solo or adventure with friends, and determine your fate in an ever-expanding world. With no level restrictions, go anywhere at any time in a truly open world. In The Elder Scrolls Online, the choice is yours.CHOOSE YOUR ADVENTURE—Begin your adventure where you like: emerge from Coldharbour in the Base Game, battle Dragons in the Elsweyr Chapter, or face the Prince of Destruction, Mehrunes Dagon, in Blackwood. All content is accessible for new players, and you can switch adventures whenever you like.