There is always terrain encounters. Sandstorms, wildfires, freak lightning storms with river flooding. It is not all Sahara Desert anymore. It is more Texas grasslands and terra-formed from the Shades.
I thought with 5e Anauroch is a desert again so the terraforming devices of the Shades have failed utterly.
I was thinking something along the lines of dealing with Bedine or Zhentarim who are (have been?) inhabiting the region. Sandstorms and such could be but after a few it could get really old.
A small fort overlooking a water hole. Pay the owner to be allowed your drink. (Have you seen the old cartoon 'Crock'?) The tough guy in charge is greedy but honorable - because he doesn't want an army swarming down on him from all points of the horizon. If you don't pay, he and his henchmen will pepper you with arrows, cantrips, &c ... and catapult a cauldron full of poison into the waterhole.
(He'll clean up the mess after you leave, either on foot or by dying of thirst or from poison. Or maybe he's a deceiver and made the water just taste bad.)
A crazy hermit who has the ability to see the future. Usually this means 'tomorrow's weather forecast' or information of similar import, but sometimes he sees something more significant. He wants a free meal and some entertainment in exchange for telling you what he has seen.
Sign of the desert: a number of buzzards circling in the sky means that a dying / dead creature is underneath them. This may be an animal or a person or somebody significant to the campaign plot arc. How this unfortunate soul came to be in this condition is up to you, gentle DM.
You think you can see the ruins of a city: a gate, columns, statue, pavement stones. Up close, it is all wind-abraded rock. Maybe it was a city a few thousand years ago...
Another trading caravan going the other way (or across your path). They might want to trade with you, or they might "my schedule is imperative", or they might be wanting to exchange their trade goods for your survival supplies. They will behave as befits legit merchants who want to make a life-long career.