I think Fran and Balthier had a particularly strong relationship because they simply depended upon each other and, simply put, were a team. Although we aren't always shown this throughout the game, the scenes at the start of FFXII are a testament to their relationship, I think. Perhaps it's overlooked because we don't see two strangers develop a bond like we do with Squall and Rinoa or Tidus and Yuna.

Otherwise, I think Cloud had rather strong bonds with both Aeris and Tifa. I think the bond with Aeris rather speaks for itself, but with Tifa he managed to get his life back on track, learn about his past and support each other throughout thick and thin. I don't think Tifa would've come across as strong a character as she did if it weren't for the fact that she did, in the end, depend on Cloud more than people think. It was nice how a childhood friendship like that was able to rekindle even after years apart.