Not that I’ve found. My favorite part of moving to a new instance is screenshotting the communities you’re in, going to the new instance and searching and … they don’t show up for some reason.
If you search by the full URL of the sub and make sure that Search is set to “All” it will show up eventually. If you then subscribe, your instance will then be federated and start to receive info from that community but it does take a bit of time to get.
If you join a medium-sized but weeks-old instance then it is likely to already have been federated and you won’t have much of a headache.