Try Hudson Tool steel they have 3/16 x 3/4 x 36" for $33.08 plus shipping in W2.
https://www.hudsontoolsteel.com/cata...stock&grade=W1
Or try Cincinnati Tool Steel, they have varieties and shear cut plate possibly something you might like such as W2 or L6, but I think the L6 is 3/8 thick. They definitely have O1 and the S series shock steels.
http://cintool.com/