One bar builds funny enough have actually been around since the beginning of The Elder Scrolls Online. One of the earliest I've heard of is actually Xynode's Lazy Sorc. That said with the release of High Isle and the "Oakensoul" Ring, One bar builds saw a popularity boost like nothing we'd ever seen before. Creating accessibility for so many players by reducing how much you need to do while still remaining effective for all content. Yes ALL content, they were so effective some friends and I got "Godslayer" with all DPS on Oakensoul builds.
So here I've started to dabble in making one bar builds that are fun, and effective while keeping it as easy as possible. There is even a tank in there!