The 1.17.1 release of my expansive dimension, worldgen and function datapack, Fluid Dimensions.

Features:

• 3 new dimensions (Underridge - underworld-like, fairly packed; Upper Sky - quite empty and not very done yet, good for building; Warp Dimension - central 'hub' that connects the worlds)
• 1 custom 'stacks' structure in the Underridge
• 1 new boss, summonable via the rare drop from a strange new mob. (Give command for creative):/function fluid_dimensions:give/stygian_iris

• 4 new enemies: Cochineals (neutral unless you approach), Haunted Armour, Psirots - these guard the Stacks - and Echoes, they use your gear against you
• 21 new items, with unique uses, including mob drops, materials, an alloy and tools for navigating the worlds
• 6 custom blocks, including naturally occuring Warp portal blocks and a custom crafter found rarely in the Stacks structure. Recipes exist for 'nulliron', an alloy material; crafting blocks from garnets and nulliron (and back); the nulliron armour set; the Universal Altimeter, Void Veil and Nadir Tunneller. A custom GUI makes it almost seamless with vanilla expectations
• 1 custom armour set, with fully working rendered model on players, armour stands etc. No leather kneecaps like regular dyed pieces

• Travel between dimensions by flying, falling, warping and 'tunnelling' through bedrock - without breaking it - with the Nadir Tunneller (works in the Nether roof as of v0.1.1)
• Navigate 5 characterful yet very hostile biomes in the Underridge, with 30 custom decoration and terrain building features. It can be a challenge even in endgame!
• Will soon hopefully be an MCD Certified Datapack, following optional style guidelines
• Original assets for all custom items, blocks and mobs in the required resource pack

Website