The two that I know of, Canjar and Kepplinger are long gone. AFAIK, there are no new set triggers for #1s  out there. Used market, maybe.

I don't have one of these but would like a non sellers opinion of it.    

Jard trigger for a Ruger #1  sold by EABCO 

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Ruger No 1 Trigger Replacement 1 lb. Pull
  Replaces the factory trigger, transfer bar, and sear with a better, one-piece design. It pivots off the factory sear pivot point instead of the original trigger pivot point, giving a mechanical advantage for lighter pulls and fine adjustment. Take-up (creep) and over travel are fully adjustable. We also have different springs for different pull weights: 1, 1¾, 2½, 3½, and 4½ lbs. 

  Beats Moyers Trigger - Moyers approach was simply to add back in the adjustments screws that the original Ruger #1 rifles used to have. It's basically a factory trigger with adjustment screws... Better than the factory trigger, but still not great. This new trigger actually changes the pivot points, resulting in leverage that makes it possible to have a much better trigger... Predictable pull weight, crisp release, with adjustable take-up and overtravel.

  Beats Kepplinger Trigger - The Kepplinger was a Set-Trigger that relied on the spring tension of the factory trigger. Pull it directly and you'd get the same pull as factory. Push it forward to "SET" position and it would be lighter than factory... But not a predictable weight, take-up, nor overtravel. It's now discontinued. This new Number One trigger gives a predictable pull weight, crisp release, with adjustable take-up and overtravel.
  Installation of the Ruger Number One trigger requires a thorough understanding of the Ruger No. 1 Trigger System. You should be familiar with disassembly and re-assembly of the receiver before attempting to install this yourself. Includes instructions.

I personally have five of the Jard triggers installed in Ruger #1 rifles. Several clients have had me install them in their #1's. I also have the Kepplinger and Canjar on rifles and see no advantage with either of them over the Jard. The Jard is adjustable for sear engagement and overtravel and additional springs can be ordered for different pull weight.
SSS