@l @sjw @p @Moon the trick is that pleroma comes with a /relay by default, and it's not too hard to scrape them from /api/v1/instance/peers

you probably already have instances in mind you want to follow
if you do not here's a thread were i post 2k relays with instructions

https://declin.eu/notice/AWDxxJ0r6SlAEZxF0i


as for federation, activitypub only works on follows, and fetching objects interacted by the people your instance follows
for details see https://blog.soykaf.com/post/activity-pub-in-pleroma/

there's also no tool made to backfill, but it should be possible
you'd have to scrape the post url's of the instances/people you want
and then fetch it via search, or script it more directly with a mix/iex task
looping over that through Pleroma.Object.Fetcher.fetch_object_from_id(id)