Silver IC's for tubed preamp/monoblocks

Any, but I like the rscables silver ic.

HI, the best silver I have heard are A Capella La Musica. I have a pair from my turntable to preamp. I wouldn't part with them. They are very expensive but, sometimes available for less on Agon.

Add Ridge Street to your list: naturally insulated silver. No Teflon, no plastic.

www.graniteaudio.com

They manufacture tube gear which is very accurate frequency responsewise and they also make interconnects, speaker cable and power cords to go with their gear -
I use thir interconnects, speaker cable and power cords in my high end solid state home theater system and they work to perfection for both multi-channel high resolution music and movies.

I know how you can get good discounts, too on their stuff.

In the micro-price, high performance arena I have greatly enjoyed Auricle Audio Design IC's by Joemazzaglia. Currently advertised for $49.99 per pair, one of the extreme bargains here on Audiogon.
His unique, handmade proprietary design RCA jacks, and multi-metal alloy wiring unite to make a very transparent, full range conduit for the glories of tube sound.
As you can tell, this is a very competitive part of the audio hobby with many worthy vendors. Therefore, the audible results in your system are likely to be fine with any of the recommendations since the comments on their websites and feedback threads already show many satisfied customers.
It seems there is upgrade potential in more than one design, and with more than one metal.