Use for teaching the alphabet sounds or RTI. These sorts include all the letters except x includes ending sounds instead of beginning sounds as students learn more about the letter x this way. All the beginning vowel sounds are short vowels so as not to confuse students with the long vowel sounds yet. And...it's common core correlated.
Please don't hesitate to ask if you have any questions, I'd be glad to help you in any way.
CCSS.ELA-Literacy.RF.K.3a - Demonstrate basic knowledge of one-to-one letter-sound correspondences by producing the primary sound or many of the most frequent sounds for each consonant.