Indicator with symbology. An alternative is to fine print english descriptions or in a mix with symbology on each air speed range as the symbols may be too large to fit so many that can be described. The aircraft model and configuration can provide more or less space around the indicator for such labeling. Deep coning in the plastic instrument panel cover can provide more space for information while increasing instrument glare shading. Color of Danger in increasing order
Green, Blue, Yellow, Orange, Red and White add explanation point
Glow in the Dark backgrounds, colored distinctions, distinctive perimeter shapes
a rotatable "bug" indicator for Take off speed or Rotation speed would be good.

As can be seen in the Marking the airspeed indicator with relevant speeds is difficult due to lack of space and the way indicated airspeed varies with weight. Some work to be done here. The manufactruer of plastice instrument covers can provide new plastic at an economical price for quick changes of aircraft. It could be possible to create deeper cones around the instruments in a thicker plastic cover, and therby create more space for icons.


Airspeed Indicator

Rpm Indicator

Fuel

VSI

Altitude