Here is a page for substitutions. I know we all do well with different sweeteners and many of you cannot have dairy.  In the past I have just written in the post what I used but from now on assume that what I write in the ingredients list is what I used or what is a very easy sub. Anything else, I will direct you to this page to make like easier for us all.  When you sub, you are testing my recipe in a different way, so I don't guarantee it will come out, so use your own judgement.
Just keep in mind these things - I don't use maple syrup. You are on your own there. Also, if you sub liquid sweetener for dry it may come out a whole other way... Or it may come out perfectly.  Also, I wouldn't substitute more stevia than what I recommend... in some recipes, it just won't come out. BUT, I usually use as much stevia as possible, so I don't think that will be a problem.  And sometimes I mention "to taste" because not all stevia powders are the same, or perhaps you are using liquid (I don't use it so I am not sure how to sub for that).
Please post on the recipe in the comments page when you substitute something and how it came out. Thanks!!

Milk - you may substitute full fat coconut milk mixed with a little water (if using over 1/4 cup, otherwise full fat is fine) or even almond milk
Cream- coconut milk, full fat.
Half and Half - full fat coconut milk is more of this consistency so it works well in ice cream recipes.
Butter - High Quality Coconut Oil or High Quality Palm Oil, organic preferred
Farm Eggs- most recipes call for large eggs which are 1/4 cup each. If you have small farm eggs, just use 1/4 cup of eggs per each egg called for. You can scramble them in a measuring cup and set aside the part you don't need, either for breakfast the next day (refrigerate) or another recipe!
2 Teaspoons of Arrowroot Starch = 3 Teaspoons (1 Tablespoon) of Cornstarch (Read more about it here).  Corn is considered a grain, and has more carbs (since you use more).

1 cup sugar =

1 cup coconut palm sugar - works well for almost any sugar sub use except coffee.
1 cup xylitol - great for cold things like ice cream
1 + 1/3 cup Erythritol - only good for baking, IMO. NOT for ice cream (yuck!)
1/2 cup agave nectar
1/3- 1/2 cup honey
1 + 1/4 cup maple syrup (plus add baking powder.  I don't use this so... you are on your own here)
1/2 teaspoon NuNaturals powdered Stevia
1/4 teaspoon Sweetleaf powdered Stevia or a good place to start if using another brand

OTHER GF FLOURS:  Don't do it. It won't turn out.  That's a WHOLE other recipe!