The shardminds were introduced in D&D 4E. So, are there any published D&D novels featuring shardminds?
I don't mind the setting of the novel (Forgotten Realms, Eberron, etc), I just need to know where it appeared.
I went on to search on the D&D Novels between late 2009 and 2015, but was unable to find any shardmind character.
Upon some extra search, I discovered that the Living Gate, from where shardminds come from, was the subject of one of the novels included in the Untold Adventures anthology (not included in the Wikipedia's list). However, there is no shardmind character or citation of that race in the "Tales of the Living Gate" chronicle.
There's a chance that a shardmind character appears in a D&D comic book, but I didn't search for it.
For the search we need a scope of time, this is achieved by searching through all relevant material, as well as making logical estimations.
All of the Shardmind material listed in the Compendium is part of the PHB 3 (release: 16.03.2010), Psionic Power, and the Dragon Magazine 387 (release: May of 2010). Wizards of the Coast launched the 5th edition in the summer of 2014, so this provides us with a reasonable timeframe from 2010-2015 which I expanded to 2009 to 2016.
Even after an extensive search through official channels and via search engines I could not find any novel that is about Shardminds. You may want to contact the customer support of WotC and ask if there is any product not listed in the compendium.
Most of the material that comes up is homebrew exportation to 3.5e or 5e. There is this product, which I do not endorse or know whether it is under Fair Use. All of it is based on the flavour from the D&D 4E PHB3 further supporting that there is a lack of any novel and material outside of the material listed above.
My research included but was not limited to keyword searches for the phrases "Shard", "Shardmind" and "Shard Mind" through all entries on amazon.com of this novel list during the period of 2010 to 2014 as endorsed by Quadratic Wizard, the keyword search (on the 10.05.2019) revealed no novel featuring Shardminds.
I further expanded my research (on the 10.05.2019) to include the rest of the books from 2009-2016, on the basis that there might be any material that inspired the race pre-rulebooks, until Hero by R.A. Salvatore, released on October 25, 2016. There are no new results.
My research doesn't conclude that there is no Shardmind novel. If there is a novel, then it is probably merely with a minor appearance of Shardminds (instead of a novel about Shardminds). That a novel went under the radar even though there is an enthusiastic community that exports the race to different systems seems unlikely.