It could be that the games taught your DD some of the sounds, enough to convince the teacher that she knew them, whereas in actual fact she might not have consolidated that learning enough to be in the spelling group. Remember that "sounds" includes blended sounds like th sh ch ge etc, plus a whole lot of vowel action (ee, ou, ie) which aren't included in ordinary alphabet cards.

There are several phonics-teaching systems with material available to support learning. Jolly phonics and Letterland are two that are commonly used in schools. Ask at your school whether they are using one of these systems, if so there may be some songs/books/web materials that you can draw on. Best idea though is to find out what the teacher is doing and just reinforce that at home, rather than trying to teach her the whole thing at home