From early TNG, I'd recommend Jean Lorrah's "Survivors" focusing on Tasha and Data, and its sequel "Metamorphosis".
From what I have read about these two novels on Memories Alpha and Beta, they seem to me to be quite independent from each other, except for their author. Is this analysis correct, or is their something I'm missing?
The basic plots are distinct, but Metamorphosis
brings back several guest characters from Survivors
and continues some of its character arcs, so there's a definite continuity. Survivors
is mainly about Tasha Yar, but it has a major Data subplot, and Data's arc from there continues in Metamorphosis
A caution, though: Keep in mind that these books were written in seasons 1-2, and it wasn't until the start of the third season that Data was codified as being emotionless. Originally, the idea was that his emotional awareness was underdeveloped, but present on a subdued level. And this is the premise explored and developed by Lorrah's novels. So the Data who appears in those books may not seem like quite the same character we know Data as today, but it was entirely consistent with what had been established about the character when the books were written. (Also, Tasha Yar's backstory in Survivors
differs in some details from what was established in "Legacy.")