We need pictures with strokes of said brushes. And please, not a complete picture where XYZ brushes were used, just take a canvas and make some strokes with the brushes you search in the programs you named above, so SAI and CSP, then we have something which allows us to point you in the right direction. Otherwise, I’m pretty sure you’ll find brushes in the links I gave you, that are pretty near to those you search.
And I forgot to mention the “Jarry H. Linebrush-Set for Krita”, which is the second most downloaded resource from my cloud, even though you can’t find it in our resource category. But people search for it on the web and Google directs them… 
And in “Fizzyflower’s ULTIMATE MyPaint Brush Collection” you’ll find a bundle called “Rudluff” (or something like that) with excellent brushes for line art. But this site is a bit hard to navigate and find the right download because of the abundance of resources, so if you need help, feel free to ask.
Michelist