As far as annuals go, winter rye or a winter rye/winter wheat mix is the only plot(s) that have shown consistent use. I tried a brassica mix last fall and it went untouched until late January and even then, it didn't get hit hard. I basically use winter rye as a nurse crop for clover, but it gets hit in late winter and early spring and in late spring it makes good cover for fawns.
Trying a mix called PowerPlant this year. Won't get it out until next week due to the weather we've been having. According to the label on the package it should not be planted until soil temps are at a consistent 65+ degrees.
I am planning to do away with the plots for the most part next season. The 2 acre PowerPlant plot will become Native Warm Season Grasses and native forbs. If the PowerPlant grows as thick as they say, it should help with weed control for getting the NWSG started.