Grimoire
monk

Override tool functionality during runtime

Ben's Gear
MissingTextureMan101

Attach tool parts to create new tools and add a whole new layer of strategy to your tool crafting!

Multitool Mod
thediamondlego

Adds a new tool that does the job of all the other tools(except hoe and screwdriver). Also has bouble the durability of a diamond tool!

Livetools
AiTechEye

Craft tools which have a life of their own - they can fight, dig, or place for you

Randomized Map-specific Ores
Piezo_

Adds two randomly created ores to each world with varying properties depending on the world's seed

Floof
Momo

Add BicBiomeCraft inspired biomes, tools, and items.

Cave explorer tool
SFENCE

Cave explorer tool to use acoustic signals for undergound exploring.

Brights
_Xenon

Adds bright stuff

A Cute Flower
lml55

Adds an innocent flower with some head armor

Noriel Sylvire's Minerals Core Modpack
Noriel_Sylvire

An API for automatically registering recipes, nodes and ore generation.

New pickaxes
Arkatron

Adds new pickaxes

Metatool
SX

Provides API to register node metadata tools along with few useful tools

Obdy
Sires

Adds some pretty OP tools :)

Darks
_Xenon

Adds dark stuff

Banshee
ElCeejo

Adds Banshees, a ghostly mob that haunts pine forests

Portal gun
AiTechEye

Portals and stuff

faction items
GigaByte

add some items to be used as prizes for special events or player achievements

Silver
Jackknife

adds silver ore and tools

Lakemaker Mod
sunnysideup

A TNT block that makes lakes/bodies of water.

Stair Pick
BrandonReese

This is a specialized pick for making stairs.

Too many ores
TeufloV

This adds 53 new ores. But most of them are useless.