Idol Precure OST1 is out on Youtube and here are my favorite tracks:
https://www.youtube.com/watch?v=9wO255SZYWI (used to introduce that one Legendary Idol, a Café Glitter staple)
https://www.youtube.com/watch?v=6fKQ29NfopA (reminds me of the Mother's Day episode, best part starting 00:32)
https://www.youtube.com/watch?v=d8GUU5bKGxw (same, another Kokoro episode BGM I like a lot)
https://www.youtube.com/watch?v=4xNUWV1204s (Meroron lost into her fond memories)