The most recent homemade personal care product I decided to try is toothpaste. I started with the recipe here and modified it somewhat.
2 TBSP coconut oil
2 TBSP vegetable glycerin
1/4 cup baking soda
30-40 drops peppermint essential oil
5-10 drops tea tree oil
Put all the ingredients into a bowl and blend thoroughly with a fork. You may have to warm the coconut oil a bit to soften it, or even melt it, as it can be quite hard at room temperature.
It makes a sort of gritty paste that isn't quite the consistency of commercial toothpaste but is pleasant to use. One difference, the baking soda is somewhat abrasive, so I've noticed it being a bit harder on my gums than normal toothpaste.
There's probably a good way to squeeze this into a used toothpaste tube (a large syringe maybe?), but I just keep it in a jar next to the sink and dip my toothbrush into it.
This stuff can end up separating a bit, especially when the weather is very hot. You may have to stir it from time to time.