There are small themed hub worlds to explore for gold bricks and so on with any characters you own in that franchise, but again you can't unlock everything in them. (nosleepgamer.com)
The mission mode is really for those who are really skilled in this game and have probably already unlocked everything from the challenge mode. (darkstation.com)
If you have enough spins you can, in theory, unlock everything on a page. (polygon.com)