We have personal limit breaks, they're called powerful cooldowns made available through building or maintaining the job gauge for X amount of time (Greased Lightning, Life of the Dragon, Darkside) e.g. Nastrond, Verflare, Bhavacakra, Bloodspiller. Skills with long cooldowns the give a powerful effect instantly like Benediction (Full heal, 0 MP, no cast), Hallowed Ground, etc. All are virtually what a "personal LB" would be, they just aren't branded as LBs and have no "gauge" but you can think of them as having a gauge that is available at the start of a fight but fills with time once used....