What isolation feet under your amp with great result?

Aftermarket footers are system, and even more so, component cassis specific. It depends on what you need or want sonically, as many of them will shift tonality slightly one way or the other. 
One I don’t see mentioned much are the Daedalus Isolation Devices (DiD’s). Steel bearings sandwiched between wood surfaces in an aluminum enclosure, as well as brass utilized. The dissimilar materials is the key and bearings in this way work way better than bearings between more metal from my experience... All ya gotta do is call Lou to purchase. Highly recommended. 
I use a mix of DiD’s, ISOacoustic IsoPucks, EVP’s and built-in still points on my preamp.

The IsoPucks (no need to pay for the higher models from what I’ve heard. They’re just for looks) work best —and very well— directly under the stock feet of my Lampizator. On my ss amp, they work best under the heat sinks rather than under the chassis portion. 
EVP’s only worked for me under my power conditioner/filter And one under an AppleTV for SiriusXM streaming when needed, but it sure does wok here (with a weight too). 
Anything else with rubber or composite rubber I have never had good luck with. Did all the tenderfoot footers, Sorbothane and so forth and always found it to slow down the bass or mess with timing somehow.

@lowrider57 the EVP’s are interesting with a powerful change in sound. I tried them under everything but as mentioned only liked them under my power filter and under an AppleTV (for some certain casual listening). They seemed to show me that a lot of gear is designed/voiced with some vibrations happening. Because with them under most of my gear, the highs freqs, presence and energy to the sound went down. I have Harbeth 40.2’s so I can’t really have anything that deadens the sound and achieve the balance I’m after.
 Maybe if one has a bright or overly energetic sound they would work well. They really do completely eliminate something. But of course YMMV. 

@t_ramey It’s been over a year since I’ve moved or inserted any but I think I recall them working pretty quick but also think there is a couple hours for the ‘draining’ to happen.?? Not a big difference but I think there was some settling or moving out of vibrations.