I've been reading stories from the Hatsune Miku rhythm game app, that almost straddles the line between urban fantasy and unexplained sci-fi. The premise is that instances of the vocaloids live in personalized virtual worlds for different (small) groups of humans. The humans can teleport to these worlds by playing a special song on their phone, or the vocaloids can project themselves as holograms from the humans' phones. It's almost sci-fi because it mostly works within constraints of technology. For example, you get booted out of the virtual world if your phone runs out of battery, and if your phone gets shorted out, it can prevent the vocaloids from projecting themselves until the phone is repaired (though if the phone still works otherwise, they can voice chat.) Also the special song can be transferred to different machines and still works. But then what makes it more fantasy is that the song and worlds are created from the humans' feelings (and if they lose the song, a new copy will appear for them,) and it works without internet connection (if one member of a group is stranded and another isn't, they could have a vocaloid relay a message.) And then just recently I read a chapter where some characters were able to access their virtual world through their dreams, without needing the song file in the first place. For me, that's what completely tipped the scale into urban fantasy.