Bukkit

I have decided to NOT update the Materials and Entities lists found below in future, simply because it's tedious and if you can't guess the ID for whatever you're interacting with, you can just turn on DebugOutput, seeing how it's actually more efficient to do so in the first place. Enable that and interact away. You'll be told what ID to use.

What to use:

Unfortunately, I'm not willing right now to sort through all these things, so I'm just going to instruct you to use Ctrl+F to guess at what you're looking for and try to find the proper way of writing it. Commas indicate a new thing, underscores basically replace spaces and are a part of the thing. Leave them there, they are as they are supposed to be. Seriously, I copied this list from Minecraft's source code. That's how serious I am.
If you still can't find the right thing, you can try enabling DebugOutput in config.yml. It'll tell you the title of the item you've done whatever with. If it has ':0' at the end, you can ignore it if you want.

Break

Materials. Don't choose items, because they're listed there too; make sure that you choose blocks that you can break.

Place

Materials. You can't really place items unless they're really special, like CAKE. Don't quote me on placing CAKE, I don't know if it actually works. It's the same as in the break note.

Mobs

Entities. If you can kill it, then it can go here.

Fish

Entities. Right now, the only supported value is DROPPED_ITEM when you're actually fishing. You can expect more fishing values when Mojang lets you fish for specific fish though. Side Note though: You CAN list a mob, like a ZOMBIE, here and players will be payed when they hook and pull a ZOMBIE.

Tools

Materials. Obviously you shouldn't choose anything that isn't a tool, but if you want, you could list AIR and give people bonuses for killing things with their fists. Or STONE and have them bash things with rocks. That'd be a fun idea. Anyways, the tool tag only applies to Mob Killing and Block Breaking, so choose wisely.

Craft

Materials. If you can craft it, it'll work here.

Smelt

Same as above. Materials, if it's cookable.

Material:

ACTIVATOR_RAIL , AIR , ANVIL , APPLE , ARROW , BAKED_POTATO , BEACON , BED , BED_BLOCK , BEDROCK , BIRCH_WOOD_STAIRS , BLAZE_POWDER , BLAZE_ROD , BOAT , BONE , BOOK , BOOK_AND_QUILL , BOOKSHELF , BOW , BOWL , BREAD , BREWING_STAND , BREWING_STAND_ITEM , BRICK , BRICK_STAIRS , BROWN_MUSHROOM , BUCKET , BURNING_FURNACE , CACTUS , CAKE , CAKE_BLOCK , CARPET , CARROT , CARROT_ITEM , CARROT_STICK , CAULDRON , CAULDRON_ITEM , CHAINMAIL_BOOTS , CHAINMAIL_CHESTPLATE , CHAINMAIL_HELMET , CHAINMAIL_LEGGINGS , CHEST , CLAY , CLAY_BALL , CLAY_BRICK , COAL , COAL_BLOCK , COAL_ORE , COBBLE_WALL , COBBLESTONE , COBBLESTONE_STAIRS , COCOA , COMMAND , COMPASS , COOKED_BEEF , COOKED_CHICKEN , COOKED_FISH , COOKIE , CROPS , DAYLIGHT_DETECTOR , DEAD_BUSH , DETECTOR_RAIL , DIAMOND , DIAMOND_AXE , DIAMOND_BARDING , DIAMOND_BLOCK , DIAMOND_BOOTS , DIAMOND_CHESTPLATE , DIAMOND_HELMET , DIAMOND_HOE , DIAMOND_LEGGINGS , DIAMOND_ORE , DIAMOND_PICKAXE , DIAMOND_SPADE , DIAMOND_SWORD , DIODE ,DIODE_BLOCK_OFF , DIODE_BLOCK_ON , DIRT , DISPENSER , DOUBLE_STEP , DRAGON_EGG , DROPPER , EGG , EMERALD , EMERALD_BLOCK , EMERALD_ORE , EMPTY_MAP , ENCHANTED_BOOK , ENCHANTMENT_TABLE , ENDER_CHEST , ENDER_PEARL , ENDER_PORTAL , ENDER_PORTAL_FRAME , ENDER_STONE , EXP_BOTTLE , EXPLOSIVE_MINECART , EYE_OF_ENDER , FEATHER , FENCE , FENCE_GATE , FERMENTED_SPIDER_EYE , FIRE , FIREBALL , FIREWORK , FIREWORK_CHARGE , FISHING_ROD , FLINT , FLINT_AND_STEEL , FLOWER_POT , FLOWER_POT_ITEM , FURNACE , GHAST_TEAR , GLASS , GLASS_BOTTLE , GLOWING_REDSTONE_ORE , GLOWSTONE , GLOWSTONE_DUST , GOLD_AXE , GOLD_BARDING , GOLD_BLOCK , GOLD_BOOTS , GOLD_CHESTPLATE , GOLD_HELMET , GOLD_HOE , GOLD_INGOT , GOLD_LEGGINGS , GOLD_NUGGET , GOLD_ORE , GOLD_PICKAXE , GOLD_PLATE , GOLD_RECORD , GOLD_SPADE , GOLD_SWORD , GOLDEN_APPLE , GOLDEN_CARROT , GRASS , GRAVEL , GREEN_RECORD , GRILLED_PORK , HARD_CLAY , HAY_BLOCK , HOPPER , HOPPER_MINECART , HUGE_MUSHROOM_1 , HUGE_MUSHROOM_2 , ICE , INK_SACK , IRON_AXE , IRON_BARDING , IRON_BLOCK , IRON_BOOTS , IRON_CHESTPLATE , IRON_DOOR , IRON_DOOR_BLOCK , IRON_FENCE , IRON_HELMET , IRON_HOE , IRON_INGOT , IRON_LEGGINGS , IRON_ORE , IRON_PICKAXE , IRON_PLATE , IRON_SPADE ,IRON_SWORD ,ITEM_FRAME ,JACK_O_LANTERN , JUKEBOX , JUNGLE_WOOD_STAIRS , LADDER , LAPIS_BLOCK , LAPIS_ORE , LAVA , LAVA_BUCKET , LEASH , LEATHER , LEATHER_BOOTS , LEATHER_CHESTPLATE , LEATHER_HELMET , LEATHER_LEGGINGS , LEAVES , LEVER , LOCKED_CHEST , LOG , LONG_GRASS , MAGMA_CREAM , MAP , MELON , MELON_BLOCK , MELON_SEEDS , MELON_STEM , MILK_BUCKET , MINECART , MOB_SPAWNER , MONSTER_EGG , MONSTER_EGGS , MOSSY_COBBLESTONE , MUSHROOM_SOUP , MYCEL , NAME_TAG , NETHER_BRICK , NETHER_BRICK_ITEM , NETHER_BRICK_STAIRS , NETHER_FENCE , NETHER_STALK , NETHER_STAR , NETHER_WARTS , NETHERRACK , NOTE_BLOCK , OBSIDIAN , PAINTING , PAPER , PISTON_BASE , PISTON_EXTENSION , PISTON_MOVING_PIECE , PISTON_STICKY_BASE , POISONOUS_POTATO , PORK , PORTAL , POTATO , POTATO_ITEM , POTION , POWERED_MINECART , POWERED_RAIL , PUMPKIN , PUMPKIN_PIE , PUMPKIN_SEEDS , PUMPKIN_STEM , QUARTZ , QUARTZ_BLOCK , QUARTZ_ORE , QUARTZ_STAIRS , RAILS , RAW_BEEF , RAW_CHICKEN , RAW_FISH , RECORD_10 , RECORD_11 , RECORD_12 , RECORD_3 , RECORD_4 , RECORD_5 , RECORD_6 , RECORD_7 , RECORD_8 , RECORD_9 , RED_MUSHROOM , RED_ROSE , REDSTONE , REDSTONE_BLOCK , REDSTONE_COMPARATOR , REDSTONE_COMPARATOR_OFF , DSTONE_COMPARATOR_ON , REDSTONE_LAMP_OFF , REDSTONE_LAMP_ON , REDSTONE_ORE , REDSTONE_TORCH_OFF , REDSTONE_TORCH_ON , REDSTONE_WIRE , ROTTEN_FLESH , SADDLE , SAND , SANDSTONE , SANDSTONE_STAIRS , SAPLING , SEEDS , SHEARS , SIGN , SIGN_POST , SKULL , SKULL_ITEM , SLIME_BALL , SMOOTH_BRICK , SMOOTH_STAIRS , SNOW , SNOW_BALL , SNOW_BLOCK , SOIL , SOUL_SAND , SPECKLED_MELON , SPIDER_EYE , SPONGE , SPRUCE_WOOD_STAIRS ,STAINED_CLAY , STATIONARY_LAVA , STATIONARY_WATER , STEP , STICK , STONE , STONE_AXE , STONE_BUTTON , STONE_HOE , STONE_PICKAXE , STONE_PLATE , STONE_SPADE , STONE_SWORD , STORAGE_MINECART , STRING , SUGAR , SUGAR_CANE , SUGAR_CANE_BLOCK , SULPHUR , THIN_GLASS , TNT , TORCH , TRAP_DOOR , TRAPPED_CHEST , TRIPWIRE , TRIPWIRE_HOOK , VINE , WALL_SIGN , WATCH , WATER , WATER_BUCKET , WATER_LILY , WEB , WHEAT , WOOD , WOOD_AXE , WOOD_BUTTON , WOOD_DOOR , WOOD_DOUBLE_STEP , WOOD_HOE , WOOD_PICKAXE , WOOD_PLATE , WOOD_SPADE , WOOD_STAIRS , WOOD_STEP , WOOD_SWORD , WOODEN_DOOR , WOOL , WORKBENCH , WRITTEN_BOOK , YELLOW_FLOWER

Entity:

ARROW , BAT , BLAZE , BOAT , CAVE_SPIDER , CHICKEN , COMPLEX_PART , COW , CREEPER , DROPPED_ITEM , EGG , ENDER_CRYSTAL , ENDER_DRAGON , ENDER_PEARL , ENDER_SIGNAL , ENDERMAN , EXPERIENCE_ORB , FALLING_BLOCK , FIREBALL , FIREWORK , FISHING_HOOK , GHAST , GIANT , HORSE , IRON_GOLEM , ITEM_FRAME , LEASH_HITCH , LIGHTNING , MAGMA_CUBE , MINECART , MINECART_CHEST , MINECART_FURNACE ,MINECART_HOPPER , MINECART_MOB_SPAWNER , MINECART_TNT , MUSHROOM_COW , OCELOT , PAINTING , PIG , PIG_ZOMBIE , PLAYER , PRIMED_TNT , SHEEP , SILVERFISH , SKELETON , SLIME , SMALL_FIREBALL , SNOWBALL , SNOWMAN , SPIDER , SPLASH_POTION , SQUID , THROWN_EXP_BOTTLE , UNKNOWN , VILLAGER , WEATHER , WITCH , WITHER , WITHER_SKULL , WOLF , ZOMBIE