In Vivid Worlds Will Kill You, @Traipse suggest the following biotic and abiotic factors you can use to answer his 🌱 Six questions you can use to create challenging environments:

Biotic factors

1. Large territorial predators
2. Coordinated pack hunters
3. Camouflage or mimicking predators
4. Mesopredators or prey with deterring, fear-inducing, or hypnotic self-defense mechanisms
5. Habitat-modifying (i.e. burrowing, dam-building, etc.) creatures
6. Behavior-altering parasites or pathogen vectors
7. Swarming insects
8. Plants with harmful self-defense mechanisms
9. Carnivorous or trapping plants
10. Highly active decomposers

Abiotic factors (you probably want no more than two of these per region)

1. Extreme temperature (intense heat or cold, sudden swings, microclimate pockets)
2. Extreme wind (gales, tornadoes, downbursts)
3. High water variability (drought, flash floods, ephemeral rivers)
4. High terrain instability (tremors, rockslides, fissures)
5. Toxic or corroding chemicals (hazardous soil minerals, acid pools)
6. Combustion (wild fires, flammable peat)
7. Low visibility (haze, fog)
8. High verticality (cliffs, overhangs, ravines, sinkholes)
9. Anomalous weather (icicle-knife hail, magnet storms, rain of frogs)
10. Harmful air (poison smog, spores)