I went on a bit of a research trip and found these sports communities with at least 1 post in the last 7 days:

Tennis: !tennis@matchpoint.zone

Hockey: !hockey@lemmy.ca

Basketball: !nba@lemmy.world

Cycling: !procycling@lemmy.world

Rugby: !rugby@sh.itjust.works

American Football: NFL !nfl@lemmy.world College Football !cfb@fanaticus.social (Fanaticus.social also has communities for individual NFL teams)

Motorsports: !motorsport@lemmy.ml

Boxing: !boxing@lemmy.world

Sports in general: !sports@beehaw.org

https://fanaticus.social is a whole sports instance, and the instance as a whole definitely passes the “at least a post per week” requirement

!hockey@lemmy.ca

There is a pinned post with the team specific communities

Football (where foot touches the ball)

• !football@lemmy.world
• !gunners@lemmy.world

!formula1@lemmy.world

!squaredcircle@lemmy.zip

Ping @GeekFTW@lemmy.zip

!olympics@sh.itjust.works