Yes, Brandon Sanderson has gone #fullsanderson and written five full novels during lockdown in 2020 and 2021. Sanderson cites this as being down to the removal of convention and work travel times during the pandemic, allowing him to spend more time on actual writing.
Four of the books are full-length, adult-oriented science fiction and fantasy. Three are in his Cosmere setting. The remaining book is a children's book which may see publication as a graphic novel. Details on the books will be released one a week, starting this Thursday via a Kickstarter campaign. The books will all be released in 2023.