You have asked, so I will answer. Which curriculum did we have actually use in third grade? Without further ado, here it is:
Reading – Mensa for Kids, K-3 book list Also, the National Spelling Bee Bookshelf titles. They change from year to year. User discretion is advised. We have had to skip some titles because of their political or occult content.
Writing – Writing with Ease, Level 1 – if your child is not yet writing well, do some more copywork. Alternatively, you can make your own sheets online. I had a book for cursive copywork with nature facts and Bible verses, titled Cursive Copywork.
Math – Math Mammoth – Light Blue Series, 3rd grade – This curriculum rocks!
Vocabulary – Wordly Wise 3000, Book 3. There is a fourth edition available, as well, but we used the third edition. It depends on whether you want to keep up with the latest lists of vocabulary words or just stick to the “old ways.”
Science – Christian Schools International Science Curriculum, 3rd grade – I only buy the student manual. We also attended science classes for homeschoolers at Ripley’s Aquarium of the Smokies.
Art – Private lessons at Art Studio of the Smokies
Bible – The Bible Story (10 blue hardback volumes) by Arthur Maxwell
If your child is ready
Both are great programs if your third grader has the ability to grasp abstract concepts like personal pronouns.
Hope this helps. Let me know in the comments or via email if you have further questions.