To be honest, abstract thinking is a very broad concept. Just as you said that you want music artistic accomplishment, it is actually to cultivate children's ability to perceive emotions, not abstract thinking. I guess what you want to say is to train children's associative ability. If so, I recommend The Rotation of the Food Competition. I found an evaluation for you in the episode "Ah Oh Toys 184". You can have a look first. When children grow up, letting them attend music appreciation classes in some general education courses in universities can greatly improve their insight and abstract thinking. It's nonsense not to go to any private music cram school