A Site-to-site transporter was a form of transporter that did not require a transporter pad.
In an alternate timeline, Tom Paris had acquired a hand-held site-to-site transporter. He and Harry Kim used the device to transport from a San Francisco street to Harry's office at Starfleet Headquarters and from the office to the Earth Spacedock in 2372. This type of transporter beamed itself along with the transported personnel. (VOY: "Non Sequitur")
In 2374, Captain Kathryn Janeway and Leonardo da Vinci used a small hand-held portable transporter to escape Tau and his henchmen. The device was controlled and activated with a tricorder and it did not transport itself along with the persons who were beamed. (VOY: "Concerning Flight")
While it was not specifically stated these units were of Starfleet design, both displayed the Starfleet dematerialization effect.