Done all free plays. Bonus missions. Side quests. Nothing is showing on my map except purple coin races, call in points and warp points. Are there any really well hidden bricks I might have missed
Did you miss a Stan Lee or True Believer, maybe?
Hoist the colours high!
When I get sad, I stop being sad and be awesome again. True story.
Check the sea at the west side of the map (around 8 o'clock from Fisky Tower, the staff with diamond head icon). There is one race there high up in the sky at helicarrier level.
I got that sea race. I have unlocked stan. I have gotten all true belivers
When you say you still have purple coin races, what are those? Try completing them too. The races do not all appear at once. Some follow a chain/tree and are unlocked as you complete the previous races.
You know the flying race that's between the twin towers near Oscorp? There's also a gold brick there, but race icon covers the brick icon. It was one of the last ones for me.