Mine is around that age, for Christmas he is having:
Thomas the Tank Activity Table (not avalible new anymore but there are lots on ebay and go for around £10 - £15 or less if you can collect)
Fisher Price Animal Train
Extra crocodile toy for animal train.
A toddle truck with bricks, like this: https://www.elc.co.uk/Wooden-Toddle-Truck---Red/123580,default,pd.html
A large Tigger cuddly toy
Stacking rings
Hide and Squeak eggs
Soft football (around £1 in Ikea, such a bargain!)
Stacking cups
Lil' Peanut Doll
Boat for his bath
Push and Go Thomas the Tank
Books (Mr Men, "Thats Not My" books, baby signing books)
I know that is a lot
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we didn't spend a lot (all second hand, reduced or bargains in other ways) but ended up with a lot of things.
As the animal train was second hand we needed to check it worked and things before putting it away, my husband brought him in the room just as I set it off and he was fascinated by it so I think it is going to be a big hit.