Kobo CA & US' A Treasure Trove of Deals sale, through October 25th, is actually pretty good if you're into mystery or travel, and also has a decent selection of speculative and non-fiction. Everything appears to be couponable/VIP-discount eligible from mostly mid-level specialty publishers (apparently distributed by Ingram?).
There's a slew of travel books from Berlitz and Insight Guides (very nice country guides with both substantial history/cultural write-ups as well as practical travel info) for just $2.99 each. Agate, who used to give us some rather nice freebies, has a number of offerings in the sale, as does Skyhorse/Arcade Publishing who've some history/biography titles as well.
For mystery and horror readers, Severn House has discounted 3 pages worth assorted somewhere-in-series titles for just $1.99, including medieval mysteries by Bernard Knight, Kate Sedley, Alys Clare, etc., later historical mysteries by Barbara Hambly, Dorothy Cannell, etc. plus some modern thrillers by Simon R. Green and Graham Masterton, and even a science fiction investigator series by Paul Johnston, set in a future Edinburgh (I bought the first half-dozen of these during a sale years ago, and really liked the 1st one which was all I've read so far). Also some mystery/thrillers for $0.99 from Oceanview Publishing, who also used to give us a lot of freebies, so you might have already read one of their authors you're interested in following up.
Linkage to the
Kobo CA main page, with categories:
Fiction,
Mystery,
Literary Fiction,
Thrillers,
Romance,
Science Fiction, Fantasy, & Horror,
Biography & Memoir,
Nonfiction (actually just 25 pages of the Berlitz and Insight travel guides; all the other non-fiction is under Biography),
Kids & Teen
Linkage to the
Kobo US main sale page. The categories are the same and the display looks like it's got almost the same selection (maybe minus a few books that only one country or the other has rights for).