ICBM

ICBM is a Minecraft Mod that introduces intercontinental ballistic missiles to Minecraft. You can target a location using a radar gun, program the coordinates into the missile launcher and send your missile off to obliterate its target

ICBM offers many different types of missile and explosives. There are hypersonic explosives which suck up blocks into a vortex and then shower them across the landscape, endothermic explosives which cover the surrounding in a layer of ice and red matter explosives which create a never-ending explosion which can devour your world.

This is the most well thought out and the best implemented explosives mods for Minecraft out there, and is definitely worth checking out.

Download: 
ICBM

Galacticraft

Build a spaceship and rocket yourself to
the moon with Galacticraft.

Have you ever wanted to launch yourself into space and explore the planets that lie beyond? Well now you can thanks to the Minecraft mod Galacticraft. With Galacticraft you can build your own spaceship inside of Minecraft and rocket yourself off to visit strange planets and moons such as Mars, Europa, Venus and Mercury. Each planet is inhabited by creatures and contains many new ores.

This mod is still a work in progress and is not completely finished yet. Minecraft fans who have always wanted to visit Uranus will have to wait as that planet is not available yet.

Download:
Galacticraft

Sonic Ether's Unbelievable Shaders

Dynamic Shadows

Sonic Ether's Unbelievable Shaders is an unbelievable mod for Minecraft that improves the graphics of the game immensely. Keep in mind that you will need a computer with pretty decent specs to be able to run Minecraft with this mod installed. The mod adds things like dynamic shadows, waving wheat and tall grass, waving leaves and fire, coloured shadows and more. The difference between playing with this mod and without it is huge, and if your computer can handle it, it is definitely recommended. 

Download:
Sonic Ether's Unbelievable Shaders

Extra Biomes

An icy Glacier biome.

Extra Biomes is a mod that adds 22 additional biomes to Minecraft. These extra biomes really help to spice up your world, espicially if you have grown tired of the same old biomes appearing over and over again.
Some examples of the biomes added are: Alps, Autumn Woods, Glacier, Ice Mountains, Rainforest, Woodlands and many more. Most of these biomes contain their own new trees and flowers, and a new terrain noise genration system is added for much more varied and epic terrain and caves.

Download:
Extra Biomes

Optifine

Extreme Lag

For those of you that don't already have Optifine, this is a mod that is likely to change your minecraft experience. Optifine doesn't add any cool new creatures or block to your game, but what it does do is give your FPS a huge boost. Have you ever been bothered by a stuttering or laggy Minecraft? Well Optifine can help, it delivers huge boosts to your FPS, and even speeds up world loading. If you ever feel that your minecraft is running too slowly, I would definitely recommend this mod.

Download:
Optifine

Explosives+

The damaged cause by a 'Mega Nuke'

Explosives+ is a Minecraft mod that adds many more explosives to the game. These include C4, Nukes, Hydrogen Bombs and Nova Bombs. It also adds other cool weapons like an elephant gun which destroys large sections of the landscape very quickly, a predator missile that you can call in from above and you can even mark a point for a stealth bomber to come in and destroy. This is an amazing and very thorough mod, and is definitely a recommended download.

Download:
Explosives+

Pokémobs

Pokémobs is a brilliant mod for all the Pokémon fans out there. It adds loads of Pokémon to the game. You can craft Pokéballs to catch them, level them up and feed them berries with different effects.
This is a mod that really has to be seen to be believed.

Download:
Pokémobs