Factory Floor puts a focus on automation and planning. Powered by Mekanism, AE2 and OpenComputers, you'll have access to plenty of ways to automate anything you could possibly need to do.
I plan on adding pvp/defense mods later on (thinking about ICBM and MFFS), but for now you'll just have to get by with Tinkers' Construct weapons.
Mods
Mekanism is the powerhouse of Factory Floor, offering the majority of power generation and resource processing, distribution, and logistics.
Applied Energistics 2 by AlgorithmX2
AE is the standard for high-density item/block storage in the modding world. AE2 provides ways to compress mind-boggling numbers of chests into a single item that can fit in your hand. Offers a high degree of logistical control.
Adds persistable, modular computers, robots, and drones to the game that can be programmed in a user-friendly Linux-based environment in Lua 5.3.
Introduces metal melting, alloying, and casting into Minecraft, along with many, many customizable components for creating personalized weapons.
Modular Powersuits by MachineMuse
Adds a set of armor to the game that can be modified with tons of plug-and-play components like heat shielding for lava/fire, night vision goggles, a jetpack, etc.
Hardcore Darkness by lumien231
Removes the minimum light level, meaning it's pitch-black at night or in enclosed rooms. Translation: Forget about maxing screen brightness and going out spelunking or monster hunting.
Adds a bunch of new biomes, with custom looks, features, plants, and trees. Spices up the visuals and exploration satisfaction from vanilla's usual plains and treeier plains scheme.
Adds a bunch of new plants and trees to the game, offering food sources in the early-game other than punching cows. The added woods and their processed forms offer a lot of options when building
Allows you to chop down an entire tree with one break of a block if you're using an axe. Makes chopping down branched or tall trees not be a chore.
Adds ores to the Nether, meaning there's something there for you other than glowstone and death. How nice.
Adds blocks to camouflage your base, allowing for secret doors through bookcases, invisible trapdoors, and more. Perfect for a pvp server.