Gene Doucette’s 2021 The Apocalypse Seven is a standalone post-apocalyptic novel.
University student Robbie wakes the morning after a raucous party to find himself alone in the Harvard dorms. He goes out to explore and finds Carol, who is flustered because she woke up and found her seeing-eye dog vanished. They search further. Cambridge appears to be deserted and overrun with wild animals. They eventually find two more people: Bethany (a teen with a talent for picking locks) and Touré (a programmer).
Further finds: Paul (former lowlife turned backwoods preacher), Win (experienced woodsperson), and, much later, Ananda (professor). Now they are the Apocalypse Seven!