Nice to see that Open Road has put a bunch of titles on sale for their old $1.99 sale price! (Also a few at $2.99.) Most of these are a few titles per author. I'm in a bit of a hurry, so I'm just listing authors and links - you'll have to go look for specific titles yourself if you need/want something by a particular author. Also note that Open Road price drops are usually only for a VERY short time, so if you want something, best to look/buy now. I've listed the number of titles on sale right now by each link, but these may go up or down as Open Road changes their pricing.
John Dickson Carr (8 titles):
https://www.amazon.com/gp/search/?se...price-asc-rank
Brett Halliday (5 titles):
https://www.amazon.com/gp/search/?se...price-asc-rank
Lawrence Sanders (5 titles):
https://www.amazon.com/gp/search/?se...price-asc-rank
Joan Hess (5 titles):
https://www.amazon.com/gp/search/?se...price-asc-rank
Ed McBain (a few at $1.99, a lot more/older prices drops at $2.49 and $2.99):
https://www.amazon.com/gp/search/?se...price-asc-rank
Raoul Whitfield (3 titles, link also includes a novella):
https://www.amazon.com/gp/search/?se...price-asc-rank
J Robert Janes (5 titles, link includes one stray):
https://www.amazon.com/gp/search/?se...price-asc-rank
EV Cunningham (pen name for Howard Fast, link includes four mysteries written as Cunningham, and several other Fast titles - he was a prolific writer):
https://www.amazon.com/gp/search/?se...price-asc-rank
ADD:
Edward Sklepowich (2 titles):
https://www.amazon.com/gp/search/?se...price-asc-rank