Harold and the Purple Crayon
Harold is a quiet, imaginative toddler who draws his entire nighttime world into existence with a purple crayon, solving every problem he creates along the way before finding his way back to bed. The book is essentially content-free from a screening standpoint: no scary characters, no conflict between people, and a warmly reassuring ending.
A perfect bedtime read for toddlers and preschoolers, roughly ages 2 and up.
Chapters to know about
Harold draws a dragon that gives him a fright, then loses his footing on a mountain he drew and ends up adrift at sea; he resolves both situations on the very next page by drawing his way out.
Harold wanders alone at night without a parent nearby, which is entirely fantasy-framed and ends with him snug in bed, but it can spark a lovely chat about feeling safe and using your imagination.