Push The Button wrote:
TNG: The Best of Both Worlds I and II and Family, as we follow Picard's story before, during and right after being assimilated by the Borg.
I prefer to stretch this a bit more, perhaps encompassing a good chunk of Season 4. Not only is the BOBW trilogy (and yes, just like you I consider it as such) significant, the theme of family and relationships is perhaps strongest in Season 4. We have episodes about the Soong Boys, Beverly's own personal connections, the departure of Wesley, an episode that explores life on the ship and a wedding through Data's eyes, and an episode that revisits Tasha Yar's past. There's even an intergalactic baby thrown into the mix! And then, the season ends with the deepest look into Worf's own life and his difficulties juggling Starfleet life with Klingon heritage.
So it might not be a complete story in the traditional sense -- I suppose if several of those episodes (and overlooked the ones that don't quite fit in), you could argue that it's more of an anthology. It's fairly clear that the writers and producers were aiming for a central theme that went beyond your standard anomalies aliens of the week. It's not an arc in your usual, serialized sense, but I feel that the theme pops up more than enough times for the thread to be visible.