Two of the 10 adventures in Dragon Delves are being advertised as being appropriate for "solo players." Today, Wizards of the Coast revealed the table of contents for Dragon Delves, a new anthology of dragon-themed adventures due out this July. Interestingly, three of the adventures - a Level 3 adventure featuring a Gold Dragon, A Level 7 adventure featuring a Bronze Dragon, and a Level 12 adventure featuring a Copper Dragon - include mentions that they are appropriate for a "solo player."
This marks the first time, at least based on our cursory search, that D&D has advertised adventures made for 1-on-1 play for Fifth Edition (NOTE: It was pointed out that the D&D Essentials Kit also could be played with one player, using the Sidekick rules to help flesh out the party.) It's notable that the adventures appear to be roleplay heavy rather than combat focused, with the Level 3 adventure involves rescuing an "unexpected prisoner" from a hag living in a cottage made of candy, while the Level 12 adventure involves finding the lost verses of a song needed to save a region's farmlands. All three adventures appear to feature metallic dragons, which are aligned towards good as opposed to evil.