I'm afraid I may be a bit of a freak!!
Used to put 18mth old in bath with baked beans/ spaghetti/ jelly etc to play with or try grated carrot, turnip etc(bath is much easier to clean than kitchen floor and walls IMO)
Also loved finding pictures in magazines etc - used to make collages of colour blue/ cars etc.
would play with plastic xmas baubles
made shakers out of old tubes etc
loved (and still loves at 5.5) making (and distroying) tents and dens to hide in
made posting boxes from old formula tins (or something similar) and gave cardboard shapes or pictures to post (old cardboard books are great for this)
Loved different brushes ie old toothbrushes/soft hairbrushes/ shaving brushes.
Can paint/draw with water on pavement outside
for actual toys as opposed to activities we had a "toy bus" near us where we could hire them out like a library, charity shops and car boot sales are also great.
Have fun