[Kreisler jr]

Probably the best known lesser known: C.M. von Weber, especially the "Konzertstück f minor" that was very influential as a model for shorter "all in one" romantic concerti. The other two concerti are a bit like highly virtuoso, a bit shallow homages to Beethoven's 1st and 5th concerti.
By Hummel esp. the b minor and a minor. AFAIR I didn't care much for Ries', Moscheles, Clementi or a bunch or earlier ones (in an anthology with Staier/Concerto Köln).
Bach's sons (often played on harpsichord) are worth checking out for early classical keyboard concerti. Schornsheim has an anthology with a few concerti by both Bach sons, pupils and other mid-18th century Germans.

 

[Kreisler jr]

There are some 50 keyboard concerti by CPE Bach and I basically gave up on getting them all. I think a very good start is the set of 6 Wq 43 and the two? double concerti.

 

[Kreisler jr]

I found the disc with Salieri and Steffan concerti played by Staier (I got this used with a wrong booklet/cover, so only have the bare disc, maybe that's why I had not remembered that disc favorably, the music is quite nice). The Steffan is linked above; unfortunately this one gets a bit disappointing after the introduction (it picks up again in the finale, though).
My favorite from that disc is Salieri's C major with a nice "operatic" slow movement.