There are many modules (adventures) published for 5E. We like the official WOTC materials and there are several third party publications Gyld has play tested as well. The levels of quality vary greatly among these third party offerings from fair to very good.
For the WOTC published material, we are impressed with the writing, story craftsmanship, and especially the tie-ins to established D&D canon. To that end, we consider, Tales From the Yawning Portal (Yawning Portal). Yawning Portal provides larger than bite-size campaigns (3-6 sessions each) - Medium Length campaigns. Each module is based upon a legacy module, now updated to the 5E ruleset. It steps through - the first module starting for lower level characters, leading up to Tomb of Horrors - a brutally crafted adventure that everyone should experience.
Are you looking for more than a one-off, but don't want to commit to a year long (or more) campaign? Tales From the Yawning Portal is the best out there..! Ask for Durnan!