ghost
commented
5 years ago I think you could use more plants, tree types per biome, and varied landmarks (Rubble, stone spikes, ponds, patches of sand, etc) to enhance the dimension visually. They do appear rather empty due to not having those elements.
Since biome IDs are extended from ~250 to ~2,000,000,000, I might consider adding some new biomes. This list may be edited for each idea that I come across, as well as new tweaks.
Mineral Reservoir
Add Aquamarine features. These could just be simple boulders and rock formations, but perhaps maybe some sort of mini structure?
Crystal Plains
Add spire features made of Hardened Glitter. These can be made using Structure NBTs.
Green Agate Jungle
Beaded Vines. These can be broken by hand and drop Beads, or Sheared to drop itself. Will hang off of Green Agate Trees. Crystal weeds may also generate as ground cover, some dealing damage if walked on. Mostly decorative.
Volcaniclands
Similar to the Geysers in the Smoldering Bog, add a sort of Fire Geyser or Ash Geyser, and it is several blocks tall, instead of a couple. In future, Shockshooter Drones may spawn here.
Static Wasteland
Currently, the biome layout is rather boring, will have to figure out a solution later. In future, Spitfire Drones may spawn here.
Mookaite Mesa
A new biome consisting of Mookaite for the surface blocks. Ores underground contain more Opals, and the biome resembles that of Mesa biomes. Plenty of empty structures made with chiselled blocks, though some larger ones may contain loot. Mobs are more like golems or constructs here.
Aquamarine Trench
A new biome with plenty of Aquamarine features, more so than Mineral Reservoirs. Will contain plenty of sea life, even some new mobs, perhaps.
Wasteland Hills
A biome that may generate adjacent to Static Wastelands. Mostly just Wasteland Stone and some rocky formations. Static Nomadic Lagrahks will still spawn here. In future, will also contain Lesser Shockshooters.
Igneous Plains
A biome that may generate adjacent to Volcaniclands. Mostly contains Burnt Trees and some Seared Crystal Growths. Volcanic Nomadic Lagrahks will still spawn here. In future, will also contain Lesser Spitfires.
Gold Biomes
A new sub-category of biomes consisting of Golden features. These range from trees, foliage, and the wildlife around it. Most of it is impure and cannot be used as Gold, but some parts can be. Underground will be populated with Gaia Gold Ore more prominently. Included in this sub-category of biomes are Lustre Hills, Glimmering Forest, and Golden Expanse. Will be rare. Most of the mobs are Golden variants, but some rare mobs may spawn.
Prismatic Steppe
A new biome based around the idea of light refraction. To be worked on later, but is central to the idea of Weapon Infusion.
Anomalous Goldstonelands
A new biome acting like a regular Goldstonelands, but with a slight twist. Unlike the regular counterpart, this place has more neutral than aggressive entities, and is predominantly dark green, mimicking Green Goldstone. This place is key to obtaining items that better boost the Purifier (or even crafting), and also has a new effect against Corrupt Mania: Mania Aegis. Landscape is similar.
Crystal Salt Dunes
A special kind of biome that will generate within or near Salt Dunes biomes. This biome contains more Rock Salt and various Crystal Salt structures. May contain new mobs, themed around withered-away creatures (Skeletons, etc.).
Gaia Hotspots
An extremely hot biome with no sign of life, with Primal Beasts emerging from springs of Superhot Magma. Exposure to this biome with improper protection will lower health down, not even Fire Resistance will help. It is also home to a special kind of Primal Beast entity. This biome is also unique for a kind of fluid, Extreme Magma, which whittles heath at drastic speeds and cannot be picked up. Perhaps may generate within Prismatic Steppe biomes.
Tourmaline Coasts
Rare coastal biomes that may appear when an adjacent biome to an Aquamarine Trench is any sort of land biome. They are mostly black, though with patches of crystal-cut Tourmaline, and have more puddles of Mineral Waters.