Phone Link, Snapdrop, KDE Connect, ShareDrop, Syncthing, Send Anywhere, Send files to TV, Samba, LocalSend, Zapya, PairDrop, BaShare, Warpinator, OnionShare, D-LAN, Dukto R6, RetroShare, LANDrop, WebWormhole, LanXchange, MobiKin Transfer for Mobile, p300, Transfer on LAN, networked-clipboard, Droid Over Wifi, shoutr, Simidude are some alternatives to NitroShare.