There are at least two incidents in the canon which suggest that lightsabers attract Force sensitives:
Ezra was attracted to Kanan's lightsaber in the pilot episode of Star Wars: Rebels TV show.
Rey was attracted to Anakin's lightsaber in Star Wars: The Force Awakens movie.
Here, the attractions are described as a call from a lightsaber. Also, in both incidents, novice Force sensitives (who didn't know that they have superpowers) were attracted. Maybe, it has to do with some weird signal they never experienced before. But, why would they experience that signal in the first place?
Is there any canon explanation (or, Legends) why lightsabers attract Force sensitives? Last I checked, lightsabers are a normal piece of technology which anyone can construct and use (although non-Force guys won't be able to fully master it). Jedi rituals (of finding crystal irregularities with the Force and building lightsaber) looks to me like a test (you may need to use the Force precisely to detect crystal irregularities) and to get to know your stuff better. Blasters certainly don't attract anyone. Is there something in lightsabers (e.g. crystals) which are active in the Force (I can't use Force sensitive word for a dead object; if you have better word/ phrase, please replace)?