Midfielders Kenny Lunt, Jamie Tolley and Glenn Southam and goalkeeper Adam Bartlett have joined the Bulls new-look squad for next season.
The quartet were all free agents, Lunt after leaving Sheffield Wednesday.
Tolley was at Macclesfield and Southam a long-serving Dagenham & Redbridge player.
Bartlett arrives from Kidderminster Harriers.
Bulls boss John Trewick told BBC Hereford and Worcester:
"I know his history. He was at Newcastle from 9 to 10 years of age until 18 and I know the goalkeeping coach who looked after him.
"I have monitored his progress for a long time and he's coming in as number-one goalkeeper.
"I've spoken to him about it. I'm delighted to welcome him to the club and I'm sure he'll do very well for us."