While they are not enforced within Infinite Flight, there are quite a few more FAA-enforced speed restrictions other than the commonly known 250kts one. According to FAR 91.117(b),
Unless otherwise authorized or required by ATC, no person may operate an aircraft at or below 2,500 feet above the surface within 4 nautical miles of the primary airport of a Class C or Class D airspace area at an indicated airspeed of more than 200 knots.
Note that the paragraph above does not apply to operations within a Class B airspace. Such operations fall under the 250kts Speed Restriction.
Also, note the following excerpt from FAR 91.117(d).
If the minimum safe airspeed for any particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed.