Hearthstone recently added additional rewards for Ranked play based on your highest rank achieved during a season. Here is some text from the announcement:
Each player’s Quest Log will display the highest rank they have reached during the month and recognize their accomplishment. Players who progress beyond rank 20 will receive a treasure chest containing an array of nifty little rewards as a way of congratulating them for their achievements. Eligible players will receive their treasure chest at the end of each season containing the season’s Ranked Play card back, one or more golden cards, and some extra Arcane Dust. What’s in the chest is determined by your highest rank over the course of the season.
Is there a list of per-rank rewards available for reference? Assuming that there are reward "tiers" as in Arena, it would be useful to know at which ranks the rewards improve significantly over the previous rank.