For children 6 years and older, the principles of Montessori can still apply. Product-wise, there is less of an emphasis on toys and more on an emphasis on daily life experiences and practical life. The child may be even old enough to use full adult size silverware and plates, and they may not need stools anymore. Accessibility begins to change for them the taller they get. They can still take nature walks and enjoy the great outdoors, and take part in trips to the museum, aquarium, etc.

The Activities Appendix in The Montessori Child is a great reference for the types of activities that you can do with your older child. Most of the activities in this section are parent involved and rely less on toys like they did in the younger years. The list is just a bunch of different ideas and isn't the end all be all list.

A way to look at it is that if you're familiar with the Montessori pedagogy of following your child and providing them the resources and means to grow your child's interest and skills, you're right on track.

That all being said, there are some ideas for toys/tools that align with Montessori’s ideals.

Gross Motor

• Playground in Backyard
• Bicycle
• Balls such as basketballs, soccer balls, etc.
• Outdoor Mud Kitchen

Fine Motor

• Phillips Screw Driver and Flat Head Screw Driver
• Combination Lock
• Hole Puncher
• Pin Pricking a shape
• Laundry folding

Science

• Microscope
• Rock Tumbling Kit
• Butterfly Growing Kit
• A World Globe like this one
• Field guides for plants (for gardening)

Reading/Writing

• Children’s Encyclopedia/Dictionary
• Continuing to read books perhaps introducing chapter books
• Lowercase labels on things around the house
• A thesaurus to encourage finding synonyms when writing
• A notebook to keep track of their everyday lives

The Arts

• Arts & Craft Kits
  • Beading Kits
  • Nicer quality paints and paper
  • Playdough or Clay to create 3D sculpture
• Music Lessons/More Advanced Instruments

Thanks to u/BamSteakPeopleCake for the suggestion!

Reference: The Montessori Child, Simone Davies & Junnifa Uzodike

For more ideas of what to get for your older child, here is Montessori Child’s Activity Starter Kit