Also, I got some different imperial sized bolts from MacB in Cork a while back when I was replacing the bolts on the engine.
Here's what they currently have in stock. Not sure of the grade, can check if you wish, but all are Zn plated.
UNC
¼ x 1/2 , 5/8, ¾, 1, 1 1/4 , 1 ¾ , 2
5/16 x ¾, 7/8, 1, 1 ¼, 2
3/8 x ¾, 1, 1 ¼, 1 ½, 1 ¾ , 2 ¼ ,2 ½
½ x 2, 2 ¼, 2 1/2 , 3 ½, 3 3/4 , 4 ½
UNF
5/16 x ¾
3/8 x ¾, 2 ½