Goalkeeper Jake Lovelace, 17, is the most well-known in the eyes of United supporters - having made his debut as a final day substitute against AFC Telford United in April.
Defender Ryan Hand, midfielder Sam Essien and striker Oliver Wilson - all aged 18 - have arrived from Fleetwood Town, FC Halifax Town and Mansfield Town respectively.
All four players will train regularly with Ian Culverhouse's first team squad.