As CMS Messages Boards may be getting added to the pack, a great addition would be signs like variable speed limit or lane direction signs like these:

for the down arrows and x that should got to RTC or TC to be added as a bulb type

as for speedsigns those idk how to do those may also be a bulb type however ill update later

IDEA: for variable speed limit signs, just replace the white area where the text would be with a black box and white text, as shown in the MUTCD