Default Communities
A well known feature from Reddit, default communities (subs on Reddit) are communities that newcomers are subscribed to by default. Lemmy, and specifically lemmy.world, could use some of these, I feel. At the very least, communities like lemmyworld, general, and newcomers are good ones to include, if we're still somehow sticking with the old Lemmy ethos of less guided interaction. Aww, pics, videos, memes, news, etc, are good ones if not. This massively sped up the integration of new users on Reddit, and I believe it's a good addition to Lemmy.
Added on to this is a capability that Reddit had and lemmy doesn't yet, which is multi(reddits) communities, or Collections is probably what we'd call them here. I could see a 'default' collection being applied to new users, for example. The pie in the sky version of this would be publicly browsable and shareable collections, so you could send your friends a link which allows them to subscribe to multiple communities at once and create a new personal Collection automatically based on it.
I would LOVE something like multireddits on Lemmy. I actually do not like the idea of default subscriptions (unless it's optional), but making custom multis is something that I'd really love to have on here.
A toggle in the signup process, checked by default, which says "subscribe me to default communities" wouldn't be too bad a compromise.
This suggestion is intended to streamline things for the average user. People who do not care about ideology, ethos, what's problematic or not, and just want to sign up and see stuff and immediately get involved in basic discussion.
This would be excellent. Even a non-general interest instance could probably benefit from having the local instance news on it's default list. Kind of useful to know when updates are scheduled.
Definitely something instance owners could define, but a specific list is not something I think needs to be defined at the code level.