Some of the makes of valve amplifier that I am experienced with, in no particular order:
Some of these brand names have been about for a very long time. The first amplifier that I ever repaired was a 1963 VOX AC30. It was only 10 years old at the time of repair, I was 8 years older than the amp! As I recall it had a noisy gain control that no longer responded to a squirt of switch cleaner.