The older TOS novel Web of the Romulans is a sequel to "Tomorrow is Yesterday" in that it's set immediately after it and the computer problems the Enterprise was having in that episode figure heavily into the plot of the book.
Both Imzadi II: Triangle and William Shatner...I think it’s The Return, or Avenger...take place the same day, immediately after the Enterprise D crashes on Veridian III. Similar cast of leads too, so you end up up assuming they had a very busy week if you read them too close together like I did. (Yes...I know the Shatnerverse is it’s own thing.)
It would be worth watching for the epic McCoy-Spock arguments alone. Leonard McCoy, Frontier Proctologist
“The Return” by William Shatner is a really good sequel to “Star Trek Generations”. Then Shatner’s “Spectre, Dark Victory & Preserver” are sequels to “Mirror, Mirror” (TOS) and “Through The Looking Glass” (DS9). “Dark Mirror” is also a sequel to “Mirror, Mirror”.
On that note, immediately after defeating the Borg in First Contact, the Enterprise-E remained in the past to take on Kang the Conqueror with the help of the X-Men in Star Trek: Second Contact.
That reminds me of an old George Carlin bit where he suggests replacing the word "Kill" with the word "Fuck" in all of those old movie clichés we grew up with...
Maybe this is what the never-produced A Time To Embrace/Refrain From Embracing would have been about?
The novel is a sequel to TOS: "The Lights of Zetar", which featured Memory Alpha. Scroll down at: https://daytonward.wordpress.com/2015/10/08/a-time-to-reminisce-looking-back-at-star-trek-a-time-to/
I always thought there should be a coda to the "A Time To" series called "I Swear It's Not Too Late." (With apologies to Pete Seeger)
If you are a Voyager fan then "Distant Shores" is a great book. A MUST read in my opinion. It is a collection of shorts stories that give background and/or follow-on to episodes. My favourite one is seeing the doctor's point of view from the episode Blink of an Eye. What did he do for 3 years? Who was his "flat mate"? What was the war? And, biggest question of all, how did he have a son? It is mentioned by someone in this thread: https://www.trekbbs.com/threads/equinox-crew.140951/page-3#post-12051902 Definitely worth the read.
It's been a long time since I've read Distand Shores. But I definitely liked it, too. Wasn't there a story that included a talent contest aboard Voyager?