Forsyth has 18 fictional works listed on his Wikipedia page, the most recent being 2018’s The Fox. Most of these are, indeed, spy novels. I think I’;ve read all of them
I think his best were undoubtedly his initial three – Day of the Jackal, The Odessa File, and The Dogs of War. You can argue that they technically aren’t “spy” novels, but they’re permeated with spies and spycraft, even if they don’t involve the CIA and KGB. In fact, one thing I like about TDotJ is that it gets away from that over-used milieu to remind us that there’s more to the world. And the OAS clearly had spies in place to see what the French government was doing.
More recently, they revived the James Bond series with a group of new writers. After Kingsley Amis wrote Colonel Sun they got John Gardner to do a series of Bond novels, then Raymond Benson to do another series. In 2009 they initiated a new series:
Devil May Care (2008)-- Sebastian Faulks – I liked it. It had the period feel of \Fleming’s books and had the grotesque villain with more grotesque henchman and a real Cold War problem at its heart.
Carte Blanche (2011) – Jeffrey Deaver – good novel by accomplished thriller writer. Updates Bond to the present day. But I probably won’t re-read it (I’ve re-read Devil may Care more than once)
Solo (2013) – Williasm Boyd – competent, but uninspiring. Puts Bond in Africa, something Fleming never did, and the movies only rarewly. Maybne that’s why it doesn’t work – wronh milieu
Trigger Mortis (2015) – Anthony Horowitz – Horiowitz is another thriller writer (and Sherlock Holmes/Moriarty writer). And he got some unpubl,ished Fleming material to work into his novel. Pretty good, and done as a period piece.
Forever and a Day (2018) – Horowitz again, and again he gets Fleming materialk to work in. Like Faulks’ book, we get the Fleming-style villain. This one is Bond at the beginning of his career. Not as good as the previous one.
With a Mind to Kill (2022) Horoiwitz’ last effort, set after Man with the Golden Gun. Not as good as the previous two, but worth reading.
Double or Nothing (2023) Kim Sherwood – just picked this up; don’t know anything about it.