Ex Machina did not feel like a standalone, more like the first in a series that never took off.
Well, you can say it feels like it, but it isn't, it's a standalone. It only relies on a movie and an episode for background, but if you disqualified a book that uses an episode and/or movie as a jumping-off point, there would be
no standalones.
Orion's Hounds is the third novel in the Titan series and therefore not a standlone. That also discounts Sword of Damocles (fourth in the Titan series),
Yeah, and
The Children of Hamlin was the third novel in the TNG series. Aside from the first two, the
Titan novels have all been standalone. It hasn't been like, say, the DS9 post-finale novels, which are heavily serialized.
Death in Winter (TNG Relaunch),
Again, being part of a series doesn't preclude being a standalone.
Death in Winter and
Q & A were both standalones.
A Burning House (fourth in the Klingon Empire series) and Day of the Vipers (prelude to a duology).
These are arguable, but I'll let you have that.
The Buried Age specifically states it is a novel of the Lost Era so it is therefore an addition to a miniseries,
A miniseries
entirely composed of standalones. The novels labelled as "Lost Era" are so called because of a time period in which they take place. They're
all standalone.
Forged in Fire, though again that could also be the beginning of a series that hasn't taken off.
Not really, no. There's no indication of it, nor that if there was another
Star Trek: Excelsior it would be the second part of the story started in
Forged in Fire (which, truly, would be "Blood Oath" anyhow).
I cannot believe I forgot about Articles of the Federation, my favourite book, being a standalone, though not for much longer as it will be added to with A Singular Destiny.
Uhm -- no.
A Singular Destiny is a follow-up to
Destiny, the "Family" to Dave's "Best of Both Worlds" in many ways, but it's not a sequel to
Articles by any stretch.
As for the MU and MyrU collections, IMO they count as anthologies and I personally would put them as a series in their own right.
Yes, but the stories aren't interdependent -- especially not the MyrU ones.