(After trying several of the larger modpacks, I would never be able to get into them. They had the ability to create complicated machines, adding thousands of items and many new and amazing mechanics, and changing the way Minecraft. However, this made them feel much to convoluted.
Certified Organic is a Modpack that aims to make a simple expansion of vanilla Minecraft without changing the feel or introducing too many new mechanics. This mod adds new biomes and dimensions, and is aimed to amplify the exploration and simple tranquility found in Minecraft.
This modpack is nothing major, no extreme changes to Minecraft. This can also be seen as a good first modpack, something to start someone off and not overwhelm them with thousands of new things.
The main mods are:
OTG/Biome Bundle
NetherEx
Betweenlands
Quark
(As you can see, there aren't too many. More dimensions may be added in future releases)

