Back to Bed, Ed! is a really cute book about a little mouse named Ed who loves getting ready for bed, but hates actually staying in bed. His parents let him come into their room night after night, until they are so exhausted they take a stand and force him to stay in his own room. The solution that works for Ed is a nice, safe, and simple one that we try with our girls too (spoiler alert - make sure they have enough of their little stuffed animal friends around to make them feel safe and happy). This is a nice book to save for the last one of the night- it reminds my girls that they have their favorite animals and that they're going to be just fine. Bedtime still isn't the easiest in our house, but Ed is helping a little bit. For now.
Another recent favorite along these same lines is Goodnight, Daniel Tiger, which walks through Daniel's bedtime routine, until he gets to the point where he is actually happy to be going to bed. My girls never get to that point, but they really like the Goodnight, Daniel Tiger song, and at the very least, it helps them calm down in the evening and at least get into bed (even if they want me to lie there with them for hours)!