The Frosted Forests (and the Glacial Taiga)
The Aether: Redux also adds another new biome, the Frosted Forests, a chilling biome covered in snow, and an abundance of Icestone. It also has a variant seen in this image, the Glacial Taiga, which has more purple trees, which are also a bit more sparse.
Upgraded Bronze Dungeon + More Mob Models
The Bronze Dungeon structure has also gotten a makeover, giving it a new, rebuilt structure along with upgraded models for its mobs!
The Blight
The Aether: Redux also adds a more dangerous new biome, The Blight, which is filled with Cockatrices and the new Blightbunny.
Skyfields
On the less dangerous side of things, the mod also adds a nice new biome known as the Skyfields. This biome has a lot of color, notably the pretty Iridia flowers and the prismatic Fieldsproot tree.
Skyroot Shrublands
Another new biome added is the Skyroot Shrublands, a landscape filled with dense bushes (and the occasional tree), along with some flowers and Coarse Aether Dirt.
New Models for various animals!
The mod adds new, upgraded models for various Aether animals, with more to come in the future!
Accessories!
The mod also adds a variety of new accessories that you can use to do various things, from reducing knockback to emitting flying embers when you hit a mob!
Cloudcaps
One of the more alien biomes in the mod, the Cloudcaps are a mushroom-filled forest, where you'll find the new Shimmercow mob, along with the little snail-like Mykapod.
The Aether: Redux
A new hostile paradise!