My cats love the Halo treats (especially the chicken and salmon)!  They are just dried meat and have no additives.  I also feed the Spot's stew with no worries as I know it is safe (and the ingredients are simple and the food looks like actual food, not ground up junk).  Good stuff.  Another good treat (which is similar to Halo's) is Grandma Lucy's (my cats love the dried whitefish).