I've got an ambitious list of post themes for my blog on kids' books(https://raisingreadersweb.wordpress.com/) In case you're interested, have a look below:

You
Board Books for Babies
Individuality
Marching to the Beat of Your Own Drum
Books to Inspire Them
All The Things that You Can Be and Do!
Finding Your Groove
Social and Emotional Intelligence
Mindfulness and Meditation
Fun Picture Books that Teach Important Lessons
Strong Girls
Overcoming Obstacles
Loosen Up and Have Fun

With Others
If You Love It, Set It Free
Learning to Get Along
Friendship
Sibling Rivalry
Are You My Mother?
Unlikely Companions
All Kinds of Love
Everyone’s Family Is Different
Bullying
Grieving

Your Life
Your Home
Food habits
Bedtime
The Dark
Bath Time
Party Time
Favourite Stuffie

The World Around You
Neighborhood
City
Nature
Gardens
Sea and Islands
Discovering the World/Travel
Making a Difference in the World
Be Good to the Planet
Weather
Seasons

All the Creatures
Silly Animals
Animals and Zoos
Farms
Butterflies
Birds
Pigs
Sheep
Cows
Owls
Bats
Fish
Cats vs. Dogs
Bears
Elephants
Squirrels
Crocodiles
Bugs
Bunnies
Dinosaurs
Penguins
Monkeys
Whales

Are They Real?
Dragons
Monsters
Witches, Zombies and Ghosts
Fairies and Goblins
Legendary Creatures

All About the Books
How to Grow a Reader
About Books, Reading and Libraries
Writing
Word Play Picture Books
Wordless Picture Books
Favourite Authors
Lovable Characters
Poetry for Kids
The Classics
Bunch of Munsch
Rhyming Picture Books
Learning to Read

The Arts
Art and Artists
Dance
Making Music
Creativity of All Sorts

Learning
Books about School
Alphabet Books
Colours
Shapes
Counting
Sounds
Fun Math Books
Careers and Such Things
STEM Books
Building
Inventors and Scientists

So Much Fun!
Silly, Silly, Silly
Fantabulous Excuses
Tall Tales
Sticky Situations
Lost and Found
The Slightly Inappropriate Books
Interactive Picture Books
Quirky
Food With Feelings

Kid-centric Themes
Astronauts, Space and Aliens
For Aspiring Cowboys and Cowgirls
Superheroes
Spies and Ninjas
Detectives
Adventure
Toys
Magicians and Magic
Robots
Hats
Pirates
Not Your Typical Truck/Car Picture Book
Not Your Typical Pink Princess Book
Planes, Trains and Automobiles
Flying
The Magic of the Box
Holidays
Valentine’s Day
Easter
Halloween
Hannukah
Christmas

Extra Special
Just Magical
Beautiful Illustrations
Fun Illustrations

Other Genres
Fractured Fairytales
Look and Find
Non-Fiction
Graphic Comics
Chapter Books with Illustrations