They are less frequent, but the What-If section has 158 entries so far. https://what-if.xkcd.com/archive/

"Less frequent" is one way to describe almost 4 years without updates. I assumed that the What-If section was dead :)

He had a column in the New York Times (https://www.nytimes.com/column/good-question-randall-munroe-...) that worked as a continuation of it in that 4 year gap.

There's a new what-if book out later this year, available at all good bookstores just in time for christmas shopping