Among the 26 vegetables,
-purple cabbage -broccoli -red lettuce
were found to contain the highest concentrations of free amino acids, B vitamins, and phenolic compounds.
https://doi.org/10.1016/j.foodchem.2020.128712
origin - https://www.pipiscrew.com/?p=19437 simultaneous-determination-of-49-amino-acids-b-vitamins-flavonoids-and-phenolic-acids-in-commonly-consumed-vegetables