These are the medal amounts available from GvG battles, according to the game's help menu.

◆ Diamond league
Round 1: 1st place: 3 medals, 2nd place: 2 medals; 3rd place: 1 medal; 4th place : 0 medals.
Round 2: 1st place: 4 medals, 2nd place: 3 medals; 3rd place: 2 medals; 4th place : 0 medals.
Round 3: 1st place: 4 medals, 2nd place: 3 medals; 3rd place: 2 medals; 4th place : 1 medal.
Round 4: 1st place: 12 medals, 2nd place: 9 medals; 3rd place: 6 medals; 4th place : 4 medals.

◆ Platinum league
Round 1: 1st place: 2 medals, 2nd place: 1 medal; 3rd place: 1 medal; 4th place : 0 medals.
Round 2: 1st place: 3 medals, 2nd place: 2 medals; 3rd place: 2 medals; 4th place : 0 medals.
Round 3: 1st place: 3 medals, 2nd place: 2 medals; 3rd place: 2 medals; 4th place : 1 medal.
Round 4: 1st place: 7 medals, 2nd place: 4 medals; 3rd place: 2 medals; 4th place : 1 medal.

◆ Gold league
Round 1: 1st place: 1 medal, 2nd place: 0 medals; 3rd place: 0 medals; 4th place : 0 medals.
Round 2: 1st place: 2 medals, 2nd place: 1 medal; 3rd place: 0 medals; 4th place : 0 medals.
Round 3: 1st place: 2 medals, 2nd place: 1 medal; 3rd place: 0 medals; 4th place : 0 medals.
Round 4: 1st place: 4 medals, 2nd place: 2 medals; 3rd place: 1 medal; 4th place : 0 medals.

◆ Silver league
Round 1: 1st place: 0 medals, 2nd place: 0 medals; 3rd place: 0 medals; 4th place : 0 medals.
Round 2: 1st place: 1 medal, 2nd place: 0 medals; 3rd place: 0 medal; 4th place : 0 medals.
Round 3: 1st place: 1 medal, 2nd place: 0 medals; 3rd place: 0 medals; 4th place : 0 medals.
Round 4: 1st place: 2 medals, 2nd place: 1 medal; 3rd place: 0 medals; 4th place : 0 medals.

Money is also given out as a reward, based on your personal contribution (amount of battle force spent on buffs) ranking within your guild.