I nominate Whiplash by Jbarron402.
Whiplash may be behind in the current standards for Racetracks, but it was a Forge Hub featured map, and is just a blast to play on with nearly any racing gametype. Be it Racetracks, Demo Racing, or even ... battletracks...
Also... Quasar is a good map, but I dislike its usage of the Shield Door elevator. It ruins the map.
You can find Whiplash in it's original Forge Hub post
Here