The History Guy
AvE's workshop videos
Anything in the military history documentary genre
This Australian group, Hindley Street Country Club, covers a really wide range of hit songs; their musicianship is incredible and the production is really tight. They feature a pile of different singers, so it seems like there's a base band that has all kinds of other singers who contribute.
https://www.youtube.com/watch?v=HJOSiJya80Q
https://www.youtube.com/watch?v=LdOctquiQ5c
The singers audio is quiet at the beginning but improves:
https://www.youtube.com/watch?v=-ig4OcmtF5c