Basics

Plants / "Proto-Crops" that were never domesticated
Often due to the time needed for Selective Breeding being longer than how long it took for another culture to introduce an existing crop
- This has led to Monocultures as well as growing non-native plants, leading to issues like Drought Tolerance
Via Genetic Engineering what took decades or GENERATIONS, can be done in years
Corn/Maize is a great example of how far something can come (this was done mostly via selective breeding)
If this level of change was appied to Cattails , Pawpaws , or Dandylions for food use, there could be many new crops
Most Cruciferous vegetables came from one "ancestor plant". Thus developing even one of the MANY potentail underdeveloped crops humanity could gain many new food ingredients, that also may grow better in some areas

Underdeveloped Crops