The T in the title stands for Terra and the new crossover storyline will cover a declining humanity that is losing its will to expand to the outer space. It will have the grand debut of the following 4 titles in the series.
Expelled from Paradise
Cowboy Bebop
Arcadia of My Youth: Endless Orbit SSX
Magic Knight Rayearth
And here is the complete list of titles that have also been featured in previous SRW series.
Mobile Suit Zeta Gundam
Mobile Suit Gundam ZZ
Mobile Suit Gundam: Char's Counterattack
Mobile Suit Gundam: Char's Counterattack - Beltorchika's Children (units only)
Mobile Suit Crossbone Gundam
Mobile Suit Crossbone Gundam: Skull Heart (units only)
Mobile Suit Crossbone Gundam: Steel 7 (units only)
Mobile Fighter G Gundam
Invincible Robo Trider G7
Aura Battler Dunbine
New Story of Aura Battler Dunbine
Armored Trooper Votoms
Armored Trooper Votoms: Big Battle
Armored Trooper Votoms: The Last Red Shoulder (units only)
The Brave Express Might Gaine
The King of Braves GaoGaiGar
Gunbuster (Aim for the Top!)
Martian Successor Nadesico: The Prince of Darkness
Getter Robo Armageddon (True Getter Robo: The Last Day of the World)
Mazinger Z: Infinity
Gun X Sword