I found...

Type what the status screen calls it (press the inventory button to see it). The list stays hidden until you do, so it can't tell you what else there is to find.

Dizzy's door key / Denzil's door key / Daisy's door key / Dozy's door key / Grand Dizzy's door key / Dora's door key / Dylan's door key
Each opens one hut's door: drop it at that door. Dizzy's own is on the beam in his hut. More: Getting out of Dizzy's hut, The other locked huts.
The key for the ground elevator / The key for Denzil's elevator / The key for Dylan's elevator / The key for Grand Dizzy's elevator
Each unlocks one elevator: drop it in the middle of the car. More: The elevator on the ground floor, The elevator near Denzil's pad, The elevator near Dylan's hut, Grand Dizzy's elevator.
A large strong plank of wood
Long and strong enough to lie across something nasty on the forest floor. More: The spikes on the forest floor.
A can of snappy weed killer
For a plant that bites. More: Something snaps at Dizzy on the first floor.
A small animal cage
For catching something that won't sit still. More: Catching the fluffle.
A long length of tough rope
For swinging from hooks: keep it, it's needed three times. More: A long rope.
A red and white mushroom
An ingredient. More: Grand Dizzy is ill.
A machine wrench
For mending a machine underground. More: The mines' elevators don't work.
An empty treasure chest
Empty, but solid: something to stand on. More: Up from the far beach.
A barrel of pirates rum
A pirate's favourite drink. More: The pirate on Dock Street's gangway.
A heavy duty rustproof pickaxe
For breaking what won't unlock. More: A locked gate under the sea.
An aqua lung for under water
For breathing under water. More: Diving into the bay, Under Silver Stream.
A large bag of salt
Salty water lifts things. More: The dangerous pond.
A large gold coin
Money, for a shop. More: A gold coin from the deep, The shopkeeper on Castle Street.
A pair of flippers for swimming
For swimming up through water. More: The far side of the bay, Under Silver Stream.
A protective old umbrella
Keeps drips and drops off Dizzy's head: the caves drip. Not needed for anything else.
Dora who has been turned into a frog!
Break the spell. More: A frog in Dora's hut.
A crossbow with lots of bolts
The prince's thanks for Dora. Fun fact: carry it to the archery and Dizzy only watches. More: The archery on Castle Street.
A heavy bag of gold coins
A troll's toll. More: The troll in the tunnel.
A tender joint of cooked ham
For a hungry creature. More: Something stops Dizzy at Crystal Falls.
A pile of dry straw
Something to burn. More: Denzil frozen in ice.
A magical star plant
An ingredient. More: Grand Dizzy is ill.
A dry match
Something to light a fire with. More: Denzil frozen in ice.
A solid gold Irish shamrock
A leprechaun's treasure. More: The little fellow on the high path, The dragon's den.
A pair of brass cymbals
Loud enough to wake anybody. More: Dozy won't wake up.
A bridgebuilder's sharp axe
Sharp enough to cut through a wooden lid. More: Under Silver Stream.
A very strong crowbar
For prising something open. More: A way down into the hull.
Some sticks of dynamite
For a wall that needs to go. More: A wall in the deepest tunnels.
A portcullis winch wheel
A castle's mechanism is missing one. More: The archery on Castle Street.
Zaks' portcullis winch handle
For a portcullis in the clouds. More: The portcullis of Zaks' castle.
A one ton weight
Heavy enough to push something open. More: A closed passage on Dora's floor.
An empty medicine bottle / An old medicine recipe / A full bottle of medicine
For Grand Dizzy. More: Grand Dizzy is ill.
A gravediggers muddy spade
For digging in a graveyard. More: Something buried in the graveyard.
A key with a skull motif
For a lift in Zaks' castle. More: The lift on the castle's lower level.
A warm golden dragon egg
A dragon doesn't burn an egg. More: The dragon's den.
A magic green bean
Plant it. More: A patch of earth that wants something planted.
A gymnasts bouncy trampet
For bouncing higher than a jump. More: Trapped in the cave under the graveyard.
A complete d.i.y. rope bridge kit
For a gap. More: The gap in the graveyard.
A small pigmy cow
To take to market. More: The shopkeeper on Castle Street.
A cage containing Pogie the fluffle
Somebody wants to look after him. More: Dylan wants help.
An empty bucket / A bucket full of water
For carrying water to a fire. More: A bucket in the cave, A fire on the castle's lower level.
A thick Persian rug
Thick enough to smother flames. More: The flames in the castle's central part.
Prince's secret sign.....
A secret: see How the game works.