I've used the "alternate" detergents for years, and find that BioKleen and Ecover are the two brands that I like the best. Both usually do a fine job by themselves, but there are a few inexpensive additives that can enhance my results:
Baking soda or washing soda are natural "sweeteners" with no smell of their own. They just help boost cleaning action and get out body oils and sweat. 1/4 to I cup per load, as needed.
Seriously smelly clothes get an additional 1/4 to 1/2 cup of borax, which also kills the kinds of mold and mildew that tend to grow in washing machines between loads, and can add their own musty smells to the wash. Borax actually smells sort of sweet, but a clean sweetness, not a perfume. It is somewhat toxic and a lung irritant, so be careful not to inhale the dust.
Up to one cup of white vinegar in the final rinse further deodorizes and cleans, removes detergent residue, and because it is slightly acidic, also softens the clothes without the toxins of fabric softeners. I also sometimes use vinegar in the wash cycle instead of soda (but not the two together, because they will neutralize each other).
If my light colors need a bit of brightening, there's a non-chlorine bleach made from concentrated hydrogen peroxide. This also kills germs effectively, as it does on wounds (but this concentrated form should never be used on the skin). It turns into water and oxygen as it breaks down, with no long-term hazard to the environment like chlorine.
Experiment with these, and I'll bet you'll find a combination that gives you a non-toxic and good-smelling wash. Over time, you'll get a sense of when an extra boost will be useful for different kinds of loads.