you can use crystals to get Epic or Crystal Block on the OH weapon, or find random items with block on the OH. the only way to get Block on non OH items is to find them on other Warrior Legend/Eternal items. if you want Block on other non Warrior non OH items, you need to Jasper those items to the other class.
@dickwad's screenshots have Block in the 4th spot on the first one, and the 5th spot on the second one. they were Jaspered from Warrior items to Rogue items.