This is a funny place to ask
That said, in terms of modern production Fostex still has a wide array at a wide array of price points. Some of the Fostex drivers tend towards the shrill, and many are of low enough Qts that they require somewhat complicated enclosures for decent LF performance.
The FE-103 drivers have been around forever to a good approximation. They're a bit tizzy without a fair amount of fiddling around -- but they're also sensitive, fun, and still fairly inexpensive.
I like the FE-207E, which had a Qts high enough to be (barely) suitable for a smallish BR enclosure. No longer made, but probably not too hard to find.
There are also many, many,
many vintage choices of no mean repute -- again, at a bevy of sizes and price points.
Have you seen the thread here on the GR Labs "Little Giant Killers"? You might want to peruse it.
This is a review and detailed measurements of the GR Research "Little Giant Killer" (LGK) 2.0 bookshelf speaker. It comes in various forms from a kit ($313) to fully finished pair ($1,038). Our DIY expert @Rick Sykora built my sample using the flatpack ($100): Rick had to do the round over on...
www.audiosciencereview.com
FWIW, I was and still am a fan of the completely unassuming little 5-1/4" twincone driver (of unknown provenance) sold by Radio Shack for many years and meant primarily as an automobile speaker: catalog number 40-1354. As Dan Schmalle ("Doc Bottlehead" of
https://bottlehead.com/) once said of this driver "It gets the midrange right" -- which it does indeed. It also manages fairly extended HF without typical whizzer "tizziness" and decent LF in, for example a TQWT enclosure. Zillions of them were sold, and they're (still) not too hard to find on the used market, and not terribly expensively, either.
I am also pretty fond of the Electrovoice "Wolverine" LS8 twincone driver. AlNiCo magnet
cast basket, sensitive and nice sounding 8" "fullrange" (extended range -- let's be honest here!) driver. Fairly common and still fairly inexpensive. Won't tolerate too much input power -- but, by the same token, it doesn't
need much, either.
(just doing some testing on a very silly open baffle)