A lot of big sites offer feeds for different categories of article, but I'm not sure it is smart to mirror every single one into a Lemmy community. The ones above, for periodicals like the BBC, are only the front page stories, which seems necessary for it not to turn into spam.
The Ars mirror, on the other hand, I broke down by category, at least partly. You can get all the articles:
Have a general support community that people can post in, and pin a post from it on the instance so people know where to post with requests and ideas. You could also include a link to the communities page or some other list of all communities that are available. It could help with discoverability
I know there's already !xkcd@lemmy.world and I wouldn't want to duplicate that community. @koraro@lemmy.world do you want me to set up an RSS bot to post new comics to the existing lemmy.world community? If one doesn't already exist? It's easy to configure the RSS bot to post comics to a designated community for them, and I think that's better than setting up a duplicate community.
Comic strips seem like they have their own communities which I don't want to collide with, and it's logical, since the frequency of posting is so much smaller that a human can do the postings no problem.