Here is the full list of all 12 Switchball trophies - there are 7 bronze, 4 silver and 1 gold.
Collect 12 silver medals
Complete Lava World
Complete all cooperative levels
Win 10 matched multiplayer races
Win 5 matched multiplayer races
Find 3 hidden paths
Complete Cave World
Collect 1 silver medal
Complete Ice World
Complete Sky World level 3
Collect 24 silver medals
Collect a Gold Medal on All levels