Background
Not much.
That might seem awfully contrite, but it's the truth. Once the war was won, there was little need for Halibel's blade. Her presence was often enough to keep the peace, and she went wherever Aizen directed her to go. The withdrawal from battle didn't bother her; there was no point in fighting when they'd already won, and if Aizen saw fit to let the shinigami live, so be it.
She spent most of her time with Apache, Mila Rose, and Sun Sun. Their company was enjoyable, and she was somewhat glad to know that they were no longer needed on the frontline. Their adoption of the human girl into their fold was surprising. Halibel was uneasy about the connection at first, but gradually relaxed when she saw that Orihime's presence made them happy. Orihime was never regarded as warmly to Halibel as the other Fraccion, but she allowed them a little more leniency when it came to their 'guest'. It may have even been possible that she'd purposely turned a blind eye towards Mila Rose's involvement in Orihime's rescue, though she would certainly impress her disapproval in the Arrancar's choice of action if only because Mila Rose had jeopardized herself.
She continues encouraging the training sessions of her Fraccion, and frequently allows them to travel with her on assignment if they so choose. There have even been rumors that she seeks to expand her trio should she find other female Arrancars worthy of her attention. (hint hint, app OC's)