Best low calorie training treats for raw fed dog

Maxi does agility and obedience so we do training every day which means a fair bit of treats. When she was on kibble I just used to take some of her daily food and use as treats and that was easy, now I'm not sure what is best?
Obviously it won't be raw (I have tried lol, but it god pretty gross, especially on the hot summer days here), but what is the best thing to use that will go alright with the raw food and that is low calorie since she is getting a fair bit in a day.
I use fruit and veggies, cooked chicken, dried liver, cheese and some dry food at the moment. Any other suggestions?

Ones you make yourself

Liver cake is very good as training treats, as is dried bits of meat, heart, liver and that

Thanks for the tips Ella!

I suppose chicken breast cooked would be the most low calorie, cheese is very fatty. Umm liver cake is ok but still quite fattening.

There's hardly any fat in liver cake especially if you water instead of milk like me