Not common, no, but...not impossible, either. I technically have an ability that I could use to travel to different worlds, but it would weaken me to the point that I might not be able to do it again for decades. Assuming it works properly at all...my interdimensional phone app hasn't been working right since I got here.

If it is right about its missing piece being in a different world, our focus would have to turn more toward finding a way to narrow that down. Searching the entire multiverse by hand is an impossible task, even with free travel between worlds. But we do have reason to think that the Fissures are...somehow close to it.