Help me think up obstructing elements for some chase rules.

[DM Magic]

I'm putting together some chase rules for 5e. In these rules, you could potentially encounter one of four things: hazards and hostile creatures that harm you; and obstructions and indifferent creatures that impede you. With the rules, I would like a set of examples for each and I'm having trouble thinking of good ones. Here's what I have so far:

Air Terrain
Hazards • Hurricane, lightning, tornado
Obstructions • Atmospheric disturbance, clouds, mountains
Hostile Creatures • Aarakocras, hippogriffs, vultures, wyverns
Indifferent Creatures • Air elementals, giant eagles, giant owls

Dungeon Terrain
Hazards • Explosive gas, falling debris, slime, toxic spores, trap
Obstructions • Crumbled passage, jammed door, portcullis, smoke, webs
Hostile Creatures • Darkmantles, dire rats, skeletons, stirges
Indifferent Creatures • Bat swarm, dwarven mining crew, rats

Underwater Terrain
Hazards • Riptide, steam vent, whirlpool
Obstructions • Coral reef, driftwood, passing ship, seaweed, ruins
Hostile Creatures • Giant eels, giant octopus, giant squid, sahuagin, sharks
Indifferent Creatures • Giant oysters, merfolk, jelly fish, seahorses

Urban Terrain
Hazards • Alchemical explosion, brawl, building gaps, street riot
Obstructions • Barrels, fence, jammed door, marketplace, smoke
Hostile Creatures • Criminal, drunks, pack animals, religious fanatic
Indifferent Creatures • Beggars, funeral procession, prostitutes

Wilderness Terrain
Hazards • Quicksand, swamp, thick mud, vines
Obstructions • Stream, fog, spider webs, thick scrub, twisted roots,
Hostile Creatures • Carnivorous plant, giant insects, owlbear
Indifferent Creatures • Lost hunters, treant, wild boars, wood sprites

 

[DM Magic]

Hello darkness my old friend...

 

[SmokeyCriminal]

You pretty much have everything covered. all that came to mind was:

Two workers holding a giant window pane for Urban Terrain, Indifferent Creatures.

and Spotting an Ex, either Hostile or Indifferent Creature. Depending on the Ex.

 

[KenNYC]

You have to have a fruit cart.

 

[Paul Farquhar]

You have to have a fruit cart.

Yes, there is ALWAYS a fruit cart or vegetable stall, no matter what the terrain.

And it is always well stocked with water melons.