Primary choristers have been using the "hotter/colder" game for many, many years for song review because it just works so well. I like to hide a lamb and have a child imagine that they are the good shepherd while they look for it. You can just as easily use any other object, maybe one that relates in some way to the monthly theme (see this post.) Have the child leave the room while someone hides the lamb. Then, invite them to return and begin looking for it. The other children give clues by singing a song louder as the seeking child comes closer ("hotter") to where the lamb is hidden and softer if the child moves away ("colder") from the spot. Keep singing the song until the object is found and then hide it again. You can repeat the same song again or use another song that needs review.
I know this idea is an old one, but they just don't come any better. It's easy and the kids never seem to tire of it. If you are new and haven't tried this game, don't wait too long. It will immediately move up on your list of effective review games.