I put in clever secrets. I grouped elements that are related together. Complete list
Stone and Cobblestone are both stone.
Gravel and Cobblestone are both broken up.
Gravel and Dirt are both ground up.
Dirt and Grass are... Duh.
Bedrock and Cobblestone are both stone.
Bedrock and Obsidian are hard.
Diamonds and Obsidian are hard.
Diamonds and Coal are both made of carbon IRL.
Coal and Wood are both plant related.
Coal and Fire cause coal to burn.
Diamonds and Iron both make tools.
Gold and Iron and both metals.
Gold and Sand. Panning for gold uses sand.
Sand and Soul Sand are both sand.
Sand and sandstone are both made of sand.
Soul Sand and Netherrack are both nether.
Soul Sand and Nether Brick are both nether.
Grass and Mycelium are both dirt covers.
Mycelium and Mushroom are both fungus.
Gold and Redstone are both ores.
Redstone and Lava are found near eachother.
Emeralds and Lava aren't too related...
Emerald and Lapis are both useless ores.
Lapis and Water are both ocean like.
Water and Ice are, well you know.
Ice and Snow are both frozen water.
Lava and Glowstone both glow.
Glowstone and Nether Wart are both Nether.
Nether Wart and TNT aren't too related...
TNT and End Stone aren't too related...
End Stone and Unknown are both mysterious.
Spawners and Unknown are both mysterious.
Clay and Brick are both clay.
Command and Brick aren't too related.
All of the bottom aren't too related. I made them random.