Are there any animated MCU series that are considered part of the main timeline?

Yes, several animated series are considered canon and part of the main MCU timeline. These include *X-Men: The Animated Series* (though its connection is more indirect), *Hulk and the Agents of S.M.A.S.H.* (less directly), and, more significantly, *What If...?*, an anthology series exploring alternate realities within the MCU. *Loki* (live action) has branched out into animated series that are also considered canon and relevant to the main MCU.