Silicon Avatar, The Outrageous Okona and Legacy are also centered around Data.
I wouldn't considered them centered around Data, although he is a prominent figure in them, but ultimately, Data is a prominent figure at almost all times on TNG, like
Clues. That episode is entirely dependent on Data throughout, even though it's not specifically centered on him. He also figures prominently in
Redemption, & Gambit as a full on B plot, about his official command experience
I also find him a wonderful component to
Déjà Q, a being finding out 1st hand what being human is, & having to associate with a being who's undergoing the same journey, in a different way. Not all that dissimilar to his use in
Tin Man. He might actually be the best part of those episodes.
What constitutes a Data episode?
Specifically? The same thing that constitutes a Geordi or Troi episode, them exclusively being the feature of focus to the story, like
Inheritance. That's a Data episode, but Data is arguably the preeminent character to the whole show, because I actually think Data's development even dwarfs Picard's. As a result, Data is constantly a feature of focus, even more than Spock was on TOS. He gets more moments of interest, like the
Schisms teaser, than any other character.
I'd consider
The Quality of Life a Data episode. I might even include it in the Data character arc, because the sci-fi concept of artificial intelligence can't be broached on the show, without it routing through him at some level, just like
The Schizoid Man. I think the only time it came up, where he isn't an influential presence is
Evolution... & maybe
Emergence
My list of what I'd consider exclusively Data episodes is...
Datalore
The Schizoid Man
The Measure of A Man
Pen Pals
Ensigns of Command
The Offspring
The Most Toys
Brothers
In Theory
Hero Worship
The Quality of Life
Descent 1 & 2
Inheritance
And
Birthright Part 1, where Worf is the B plot, that's prepping the second half which is all him. I also consider
Data's Day a Data episode, but it's unique, because it isn't about him at all really. It's about how he sees everyone else, akin to Hawkeye's "Dear Dad" episodes from the show
M*A*S*H
Masks is a tough call, because It's not really about him. It's more a Brent Spiner episode, &
Thine Own Self is debatable, because in some ways it seems like a Data episode, with Troi as a B plot, but she's in it enough that it might also be considered a fully shared episode
Interestingly enough, I don't consider
Elementary, Dear Data a Data Episode, even though he's named in it, & it does feature an emerging AI. Oddly, that episode isn't even really about him at all, once he's done being used as the catalyst.
Edit: Man, that was a much longer post than I expected it to be lol
