What are some of your must-haves when making your stories, worlds, or maps?

Whether it be meta tools or apps, or literal concepts like a mineral or a race, for example, a must for me is for the world to be built in a believable manner, and at the most simple, following some decent climate rules without much restraint.

my favourite would be drip plume ice worlds with hotspots that allow for rainforests in 80 Celsius steam zones, very exotic, the temperature regulated by these hotspots.

I rambled on too much...