Sniffer on moss block
Sniffer will drops spores blossom/Small dripleaf when sniffed on moss blocks.
Trophy banners
Add some Ominous banner-like banners as trophy. Obtains via boss drops, Shepherd Villager's gifts (Hero of the Village),...
Sleep without set respawn point
Sneak and right-click a bed to sleep without changing your respawn point.
Bonemeal Coral fan/block
Coral fans and Coral blocks can be bonemeal (only in warm ocean biome) to grow into coral reef
Faster copper block oxidation
Copper block and its variations oxidize faster in rain and water.
Sneaking sweet berry
Sneaking through sweet berry bushes. Wearing pants protects you from sweet berry bush damage.
Pat your pet
Interact with your pets via shift + right-click (wolf, cat, horse, parrot) to pat them.
Egg auto hatch after despawn
Chicken eggs on ground will try to hatch after it despawned.
Explosive sniffer
Right-click powder (gun powder, blaze powder, sugar, redstone, glowstone dust) to Sniffer will make it sniffs and... "To teach kids never to sniff something unknown." - Faewulf
Usable empty suspicious sand/gravel
You can add items (by shift right-click) into empty suspicious sand and gravel.