From mystery, you can nab High Five and a bunch of other Janet Evanovich novels for $2.99 each, as well as "Robert Galbraith's" (AKA JK Rowling) The Cuckoo's Calling for $3.99 (well worth it), and Grafton's "A" is for Alibi (launch of maybe the best ongoing modern detective series) for $2.99.
In literary fiction, North and South by John Jakes is $1.99; Conroy's The Prince of Tides (also not part of a series) is $1.99; and Alice Walker's The Color Purple (yet another non-series book) is $1.99.
In SF, VE Schwab's Villains is $2.99; All three Star Trek: Voyager: String Theory books are going for $.99 each; Scalzi's Old Man's War (has anyone not read this one) is $2.99; Pratchett's The Color of Magic (same question) is $1.99; Nnedi Okorafor's Binti is $1.99 (and the sequel is only $3.99); Vonnegut's The Sirens of Titan (which is not part of a series) is $1.99; Malka Older's fantastic debut Infomocracy is $2.99; and the first six Dresden Files novels are part of a "boxed set" for $7.99.
In non-Kindle deals, there's a 1-day huge Anime Sale, with Blu-Ray deals on One Piece, Cowboy Bebop, Black Butler, Evangelion, and a lot more. Some of the deals are at 75% off.
There's also a magazine subscription 1-day sale, with Rolling Stone for $4, New York and Martha Stewart Living for $5, and a solid amount of cooking and family magazines for $4 and under.
There's a huge Hasbro 1-Day Sale, with deals on My Little Pony (including some weird Rubik's Cube Pinkie Pie), WWE figures, Despibcable Me, furReal Friends, Don't Spill the Beans, Beyblade, Star Wars, Mrs. Potato Head (only $3.14!), and more!
In board games, Caverna: The Cave Farmers (a very solid worker placement game) is on sale for $56.35 (42% off, and about $11 below what you'll pay elsewhere), while Santorini (which I haven't played, but have heard good things about) is $29.95 (about $9 below other deals), and the tenth anniversary edition of Notre Dame is $26.83 (about $9 off as well).
And finally, in video games, Destiny 2 for the PS4 is a DotD for $25.95 (57% off).