When I look for good combing conditioners, I first look to make sure there aren't bad ingredients in them rather than look for certain good ones at the beginning. Then if I don't see anything bad, I look to see where the things I like to see in a combing conditioner are in the ingredients list. (For rinsing conditioners, I look first to see if there aren't bad ingredients, then check to make sure they look watery enough to rinse easily from our hair).

Ingredients I look for in a combing conditioner:
The big first three ingredients after water (and in this order) are: weight ingredients, slippery ingredients, then I like to see some moisturizing ingredients.

When I say water, this comes in many forms. A long list of plant ingredients really boils down to just flavored water, so it counts just as one thing: water. I usually ignore it and move on to other ingredients.

For weight ingredients, these are the most popular: stearyl alcohol, cetyl alcohol, cetearyl alcohol. These work well. There's also Benzalkonium metholsulfate.

For slippery ingredients (this helps get the comb through natual hair), there is glycerin, cyclopentasiloxane, or silicones. These ingredient types are the workhorses of your conditioner.

I do like to see moisturizing ingredients (even though if there aren't many in a product, I can add a tiny bit of olive oil to the bottle, or smooth a bit of olive or coconut oil to my ends before braiding them up at night to make up for it).

Good moisturizing ingredients are usually natural oils like olive, shea, jojoba, coconut, or palm.

Also check to make sure your conditioner doesn't have any sticky/holding ingredients. These tend to keep your comb from gliding through your hair and will build up. Avoid products with ingredients that have names with copoly anything in them, acrylate anything, vinyl anything, or PVP.

Also, avoid products with rubbing alcohol in them such as SD alcohol 40, isopropyl alcohol, or ethyl alcohol, because these can dry out your hair.

After finding a conditioner that looks good, I take it home, research any ingredients I don't recognize, add them to the Ingredients Dictionary. If everything still looks good, then I comb my hair with it, and use it to refresh my curls every morning for a week. If my hair feels good by the end of the week, and isn't dry, sticky, crunchy, matted, or has white gunk in it, then I recommend the conditioner for combing.

I know this is a lot to look for. You can always check out my recommended combing conditioners for the conditioners I really like. And you can also check out your ingredients in the Ingredients Dictionary to be sure of what's in your product. (And I'm constantly adding to the dictionary as I try new products.)