Alright, cool. I was actually just reading the synopses of his books and was already thinking they sounded like what I was looking for. I've just seen every TNG episode at least five or six times and I crave more.
Please drunkenly give additional info at your leisure
So there are still a few boxes not shown and more books elsewhere. I'm not joking when I said I can supply you.
RECOMMENDS:
Almost any book written by an actor is pretty good. Stitch in Time (by Andrew J Robinson) is the GOAT. I, Q (by John deLancie) also really good.
William Shatner books are... a trip. I know you requested TNG specifically so I would recommend to you "The Return" which is like a sequel to generations with Kirk & Picard teaming up... more.
Federation - The best Trek book I've ever read. Not even trek, just a great scifi novel,
period. I bought a hard cover copy just to have so you can have my paperback. It's a TNG/TOS crossover that is just amazing. If I had to recommend just ONE Trek book to Trek fans - literally if you're a Trek fan and you had to read one and only one trek book, I would recommend that one.
The original "mega series crossovers" I would also highly recommend as they are great "episode of" with the series, but connecting all of them in creative ways.
Invasion and
Day of Honor are definitely recommends.
Captain's Table is... pretty decent if you want to have fun with the captains.
The Q Continuum trilogy... it's like a multi-part Q episode in TNG, I would recommend it if you enjoy Q and want to see a hard working writer furiously patch over some of the weird continuity gaffs in Trek. I had a lot of fun with it, but I know it may bug some people.
Again, anything with Michael Jan Friedman was a favorite. Looking in the box, Crossover (the TOS crew still alive reunite in TNG era), Kahless (the backstory of the great Kahless himself), Reunion (backstory & reunion with the stargazer crew), all great.
Vendetta - I know it's Peter David, but it's borg related, not Q. If you want another BOBW 2-parter feeling, get it. Dark Mirror ALSO highly recommended. It's like the "lost" TNG mirror universe episode.
Otherwise, again the ones with numbers?



Those will 100% read like an episode because that's really what they were pitched as. Those are like lost episodes, a lot of the others are more like lost movies. Debors' Planet, for example? Well that's a ferengi episode. (Oh yeah... Requiem was Picard and the gorn. THAT was a really solid read.)
EDIT: Obviously I did not address any books which are literally just novelizations of episodes or movies. I figured you would already know if you wanted those or not.
(I do recommend the Trek 5 novelization though. It hilariously fixes all the movie's plot holes.)
EDIT: Oh yeah, and if anyone wants more details, you can ask and I'll spoiler the answers.