Velbon (tripods) - Faultless. I have a decades old Sherpa tripod and the quick release lever broke. They sent me a replacement FOC.
Schaller - faultless. While I was restoring the Gibson Victory it had a broken tuner (screw broke inside the capstan). Turns out the tuners were Gibson branded M4S units. I emailed them asking for a replacement capstan and screw, asking for a price of course. They sent me FOC 4x the parts I was looking for, a sticker and a bunch of picks. Was emailing back and forth with the MD most of the time too. They had absolutely zero obligation to do anything. Respect.
AMD (computer processors) - bit of a funny one this. I was looking to buy a K6-III processor to replace my K6-2 and couldn't find one anywhere. So I guessed the email address of someone fairly high up in the company who was quoted in an article online and had a good moan about availability and asking where I could find one. I guessed correctly and to my amazement, she replied. Not to tell me to naff off - quite the opposite. My brass neck must have impressed because she offered to send me one FOC and asked if that would make the situation better! Hell yeah! She wasn't joking and a few days later I received a 450MHz K6-III. It was a good 'un too, overclocked to 500MHz no bother. Still dumbfounded to this day.