Here a selection of some sites concerning telegraphy, collectors, brands or originators of manipulators.

History and Collectors

Key collection (OZ2CPU)
N1FN
Sparks telegraph key review
W1TP Museum

Manufacturers

CT (Ukraine)
G4ZPY (Angleterre)
GHD (Japon)
Hi Mound (Japon)
I2RTF (Italie)
JRC (Japon)
KC0AFX (Ukraine)
KE6RIE (USA)
Kent (Angleterre)
March (K4QU)
Milestone Technologies
Nye Corporation (USA)
Schurr (Allemagne)
SRS (Suède)
TE NE KE (Canada)
Vibroplex and Bencher (USA)
W1SFR (USA)
WB9LPU (USA)
WV7U (USA)

If a link does not work or you want to suggest one, please write to me ;-)