It looks like Sonic Frontiers will have DLC, based on this promo

Sega selling add-on content isn't too surprising, but we may have our first soft confirmation of Sonic Frontiers DLC.

Monster Hunter DLC coming to Sonic Frontiers for free on November 14th - My Nintendo News

Sonic Frontiers - PlayStation 5 : Sega of America Inc: Everything Else

Sonic Frontiers (2022), Xbox Series X, S Game

Sonic Frontiers might actually be Sonic Adventure 3

Sonic Frontiers Is Getting 'Multiple' Free DLC Content Updates Over the Coming Months

Sonic Frontiers Prologue is Now Live: Prepare for Sonic's New Adventure!

Sonic News Nintendo Life

Sonic Frontiers Limited release Shoes DLC XBOX (N.A. region)

Rumor: Sonic Frontiers Release Date And DLC Info Potentially Leaked – NintendoSoup

Sega says Sonic Frontiers sales exceeded expectations

SEGA unveils post-launch roadmap for Sonic Frontiers

Sonic Frontiers Update 3: New Confirmed Content + Coming Soon?

Sonic Frontiers – how to get Sonic's Soap shoes from Sonic Adventure 2 for free