I make my own treats all the time since I have one dog that is on a vegetarian diet. Peanut butter is a good ingredient, so are blueberries and bananas. We use oat flour in all the treats we make and substitute maple syrup for sugar.
http://www.dogtreatkitchen.com/blueberry-dog-treat.html
That’s the recipe we used as a starter and have experimented since then.
Small quantities of apple make a great dog treat. Our dog Crusher loves them.
We try to avoid seeds and stems and we don’t offer him dehydrated apple slices.
In the summer time frozen apple pieces are one of Crushers favorite treats!
Our 10 month old chocolate lab loves apples as a special treat. You can also make apple ice cubes we slices of apples drop them in the water in an ice cube tray.
My girl pups LOVE apples; my little guy eats them – he’ not impressed.
There is a handy and colorful chart on Woofipedia of common people foods showing which are pet safe and which are not: http://www.woofipedia.com/articles/which-foods-are-safe-to-feed-your-pet. Note the safe foods are only given in moderation. My Westie goes for all of the foods on the safe side except banana.