You buy thisSensory2½–4 yrsAt home
Kinetic sand
Sand that behaves, mostly.

Kinetic sandView on Amazon
Prep
2 min
Mess
High
How to play
Squeeze it, cut it, press moulds into it, bury small toys. It clumps instead of scattering, which makes indoor sand survivable.
What you need
A pack of kinetic sand and a deep tray.
What it secretly builds
SensorySqueezing and cutting is deep pressure through the hands, which most children find genuinely calming — a good one for the hour before bed.
Safety first
Tray on the floor, not the table, and a sheet underneath if your floor has gaps.