Agave Nectar, the high frutose health food fraud
Raw green stevia or fruit juices work for me.
Zemphira: I use the liquid Stevia drops in conjecture with other sweeteners. I find I can add some overall sweetness and use less date/agave/honey while still keeping the aftertaste far enough in the background that I don't notice it. Especially in tart or otherwise flavorful items. I've also blended in a few fresh leaves without tasting them at all but I'm not sure if they were enough to add anything to the overall sweetness. I killed my stevia plant pretty quickly so I didn't get to experiment with the fresh leaves much.
Agave nectar, even if it's "raw", is just a sweetener. As long as you use it minimally (maybe a tsp or two in a recipe), it really doesn't matter.
Here's an article I wrote about "raw" sweeteners: