Connetix

Connetix Rainbow Geometry Pack, 30 Pieces

Connetix tiles are thicker and use stronger magnets than most competitors, which is the main thing parents notice when switching from another brand. This 30-piece geometry pack (squares, triangles, and hexagons) is the most reliably available Connetix set on Amazon; the brand sells most of its bigger sets directly through its own site rather than through US Amazon listings.