IdiotKraft is a beginner-friendly, tech, adventure, and fantasy modpack.
Disclaimer: This is a Forge Modpack for 1.12.2
IdiotKraft is a modpack I originally developed for my friends, but I ended up adding a lot of cool stuff to it, so I am now making it a kind-of official pack.
This pack is great for beginners and adds all the essential mods that I think would be needed to get started with modded (Tinkers Construct, Applied Energistics 2, Twilight Forest, Mystical Agriculture etc.)
I added the Biome Bundle O' Plenty mod to this for new and fun biomes (and great views).
This pack has a lot of stuff to do. Tinker's Construct adds many things for making custom tools and weapons, you can build smelteries to combine (alloy) metals from different mods and have an insane number of combinations.
You can mess around with the tech mods like Tech Reborn and Applied Energistics 2 to make storage systems, automated-crafting, electricity-related stuff (many different kinds of machines).
The Twilight Forest mod adds a lot more adventure and new content for Minecraft. It adds a new dimension called 'The Twilight Forest' which adds seven bosses (The Naga, Twilight Lich, Elsa, etcetera)
Mystical Agriculture adds in a heck of a lot of new crops to start farming more than just food crops.
A lot of new armor and weapons are added and it is an all-around great experience for new players.
I recommend trying this on a multiplayer server with friends as it makes it a lot more fun!
This mod will around help you get accustomed to the modded world, and allow you to start playing bigger modpacks and understand them easier.
This modpack is very server friendly, and can run from around 2-4GB of RAM. If you wanted to you could further optimize it by deleting some of the extra mods like Genesis (by me), Tinker's Complement, Tiny Progressions (these are just examples, you can delete whatever you want to).