Holman signs on after 38 appearances and 10 goals for Brisbane Roar, while D'Agostino boasts nine appearances and two goals throughout an injury-interrupted career so far.
As part of the new contract, Holman will no occupy Brisbane's marquee spot for next season, fitting within Roar's salary cap, thus allowing the club - also without Massimo Maccarone - to pursue a marquee talent for next season's title tilt. 
“I’m really happy to continue my playing career in Brisbane and I can’t wait to wear orange again in 2018/19," Holman said.
“It’s onwards and upwards from here and I’m excited about what the future holds. The group is hungry for success and I’m looking forward to helping the team challenge for another title.”
Coach John Aloisi saw the re-signings as proof that the club is moving in the right direction.
“We’re are pleased that two more talented players have committed their futures to our Club. We are confident that Brett and Nick will have important roles to play in our success moving forward," Aloisi said.
“Both players will give us depth and further options in the front third with the qualities they possess.
“I am pleased with how the squad is taking shape as we look to have a successful 2018/19 campaign and we build for the future.”
Brisbane Roar FC 2018/19 squad:
Goalkeepers: Brendan WHITE, Jamie YOUNG
Defenders: Daniel BOWLES, Luke DEVERE, Jack HINGERT, Dane INGHAM, Connor O'TOOLE, Avram PAPADOPOULOS
Midfielders: Joe CALETTI, Thomas KRISTENSEN, Matt MCKAY, Jacob PEPPER
Attackers: Eric BAUTHEAC, Shannon BRADY, Nicholas D’AGOSTINO, HENRIQUE, Brett HOLMAN, Adam TAGGART, Dylan WENZEL-HALLS