ESO lighting furnitures have been rather annoying. They have glare but do not much spread light around.
But now there are perfect lights. Sadly they are no longer available since they were few days purchaseable from Luxury Furniture vendor.
The lights are Culanda Stone, Glowing and Varla Stone, Glowing. The Culanda Stone spreads warm yellow light and Varla Stone cold blueish light. When placed close to each other they together spread whiteish light.
The stones are not interactable. The light is always on.
Here is a sample of lighting up a large areas:
The lights are visible as small crystals. On the left side two are visible against the gray background.
Here bottom left corner is without crystals.
Note a Common Lantern at right corner. The light from it hardly reaches to bottom of the nearest pillar.
Before these i used Daedric Chandelier, Ritual as they had best light area before these stones and not too annoying glare.
Here on left is Redguard Candelabra and next to it in the middle is Daedric Candelabra. They have to be much lower than the crystals for the light to reach the floor.
The Clockwork Tower Illuminator is not bad either, but a bit dim compared to the crystals and is big on floor.
I still use Argonian mud lights, various street lamps and Common Lantern (either stationary or hanging) for local illumination.
The worst light ever: Nord Triple Torch – the eye searer.