Reading how some USA states have Share time during their weekly activities, it sounds quite similar to show & tell but is themed rather than the children bring in a general object.
Ideas for a seasonal share list ..
Spring :
Something Green
Something that is growing
An animal baby
It can be used in the garden.
'Mini beasts'
Summer :
Something yellow
You could use it at the Beach
Anything Water (interesting to see how it could be interpreted
) A wild animal
A hat
A leaflet on somewhere to go
Autumn :
Fallen leaves
Something you can 'Harvest'
The colour Brown
Hibernation
Winter :
'Does it look 'cold ?'
Something that keeps you warm
The Arctic
Something 'Christmas'
About me :
Bring in a photo
Something you collect
Favourite toy
Something you made
Something in your favourite colour
A Book to share
Letter of the week also follows the same idea !
Others 'Its'...
'It has writing on'
'It was kept on a shelf'
'It can be plugged in'
'It makes a noise'
'It Bounces'
Is this an activity you use in your setting?