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…
Seeing as how this has persisted through both my longest-lasting conworld and my most detailed conworld, I’d say a race of sapient doglike creatures. While part of the appeal of of dog ownership is that, compared to humans, dogs are emotionally simple critters with uncomplicated needs, A big part of me wishes I could explain things to my dogs in a way they could understand, and that they had the capacity to unambiguously tell me how they’re doing. I also wish I didn’t have to keep burying them every 10-15 years. Ergo, sapient cynoids that live over 7 centuries it is.
Unrelated, but I would draw maps when I was a kid, just an island with blobby regions representing biomes or polities or whatever. There would ALWAYS be a lake of lava somewhere on the map.
Oh, and mechs. Big ol’ stompy walking war crimes. Combine this with the sapient dogs and you get space doggos piloting mecha-Clifford into battle, good times.