Unlimited Boost (アンリミテッドブースト Anrimiteddo Bāsuto) is the name given to the mechanic to create Z/XToken based on various Z/X users, as well as being the Tribe used on those Tokens and the nickname used to refer to them.
"Ignition Overboost", where Z/X user and partner Z/X that was tied by bonds united as one. "Alter Break", acknowledge and overcome the "Nightmare"—materialized what-if condition, and incorporating it as a part of oneself.
Under the influence of Idea and Dream Key, as well as being pushed to their limit by struggles against Sol and the Curator over the Cthulhu, the two different abilities that was rooted in bonds are overlapping.... The "Dream" where both partner were able to fight side by side has become reality. The Z/X users are now able to use the Ignition Overboost ability on their own. This new "Unlimited (Over) Boost" method that brought unprecedented strengths to the Z/X users is also referred to as "ULOB" among those concerned.
On the other hand, the partner Z/X of Z/X users that has mastered the Unlimited Boost also gained a new power. It is possible for them to utilize the incorporated nightmare as one of the causality, "Alter Shift".
While it was concluded that those new powers are attributed to the principle of Dreamworld, the truth behind them are still unknown.