Galacticraft

This mod gives us the ability to travel to other planets, and has Solar Panels which generate energy without using fuel! The Electric Arc Furnace can smelt your minerals and produce 2 ingots!

Note 1	Galacticraft uses the RF API, which makes it compatible with machines from other mods that also use RF power, such as Buildcraft, Applied Energistics, and Railcraft. You can change whether Galacticraft displays its power unites in gJ or RF in the config file.
Note 2	If you have the Buildcraft mod installed, if may be possible to craft Sealable versions of Buildcraft pipes, which makes it possible to line pipes to and from your space base on other planets, and keep your base sealed from the airless environments.

Buildcraft

This mod adds pipes to transport items around. It also has a quarry that enables you to mine large portions of the land. At the higher-tier of this mod you can use robots and control them with gates.

Note 1	In the mod's config file, there is an option to enable an additional recipe for Pipe Sealant, by crafting it using Slimeballs.
Note 2	If you leave your engines on but not powering anything, they will explode! There is an option in the config file to enable/disable this. If the Redstone Engine overheats, it will only destroy itself, whereas the other two engines will leave a hole!
Note 3	Buildcraft has a world generation feature called a Water Spring. It's basically a 1x1 hole of water that goes from bedrock all the way to the surface. You can disable the generation of Water Springs in the config file. source

Railcraft

Who doesn't love trains? Adds extra tracks, and a sophisticated transportation system. This mod also adds large multi-block tanks to hold various liquids.

Applied Energistics 2

The ability to manipulate matter and energy to store items as data onto hard drives. Get your system advanced enough and you can utilize auto-crafting.

Biomes O' Plenty

I grew tired of boring vanilla Minecraft. This mod adds extra biomes, more trees, more foods, thus making the land twice as more varied and interesting. There's even changes the Nether. Adds quicksand and pools of poison. Adds Scythes which can cut all the leaves off of trees!

Note	Dead Wood cannot be crafted into Planks, so its only use is to be smelted into Charcoal.

Project Red

Upgrade your Redstone to Redstone Wire, with vast improvements. Create digital circuits using dedicated logic gates, and have advanced control over your machines. Save your circuits into a single block, and reuse them to create bigger circuits! Also has backpacks that are kind of like more inventory space that you can take with you!

Project Red Transportation Source Video 1 (2014) - https://www.youtube.com/watch?v=PKclsUvBhGY

Project Red Transportation Source Video 2 (2016) - https://www.youtube.com/watch?v=z7q2lV924wU

Dynamic Surroundings

Quark

Quark adds a bunch of little things to enhance the Minecraft experience. This mod only adds vanilla-like features that don't compromise the vanilla gameplay.

Other Mods

Just Enough Items & Hwyla	It is essential to have Just Enough Items, which lists the entire library of items and blocks available to you. Enable cheat mode to click and spawn things into the world. (Cheat mode only works if you are allowed to enter Creative Mode). Many mods have Hwyla integration and will display extra information in a box at the top of the screen for whatever you look at.
SoundFilters	Adds a really cool reverb effect whenever you're in a cave or underneath a hanging. Also muffles noise when you are submerged in a liquid. You must configure to your preference!
MapWriter 2	A very useful mod. Continuously scans the nearby environment and displays a mini-map in the corner. Press the 'Map' button to view the World Map. Right-click to set Waypoints, and hit 'T' to teleport to those waypoints. (Only ops can teleport).