>>96085023
>>96085095
I assume you have Mass Hysteria and Concordant Crossroads to give everything haste. Anger and Enduring Courage will be useful for giving your shit haste too.

Brave the Sands will give all your creatures vigilance and allow them to block an additional creature each turn. Serra's Blessing will just give them vigilance.

I don't really know of any cards that will force everyone to block all the time. Green has a bunch of creatures and end of turn effects that must be blocked but I don't think they're very good.

As for a white dragon, maybe Ancestor Dragon??? Since it's the biggest white dragon I can find on Scryfall. But personally pic related looks kinda cool