Plenty of plants with complete amino acid profiles..
cannabis seeds, millet, chlorella, quinoa, seaweed, farrow, stinging nettle, buckwheat, edamame, amaranth, chia seeds, spirulina...
Teff has 8 of 9, not bad going for a grain.
Not sure why the above claims edamame and quinoa are incomplete, not the sort of thing you’d expect mixed opinion over. I’ll double check my sources.
Quinoa..
https://www.hsph.harvard.edu/nutritionsource/food-features/quinoa/
‘Unlike some plant proteins, quinoa is a complete protein, meaning that it contains all nine essential amino acids’
Edamame..
https://www.medicalnewstoday.com/articles/280285
‘Complete protein: As with meat and dairy products, it provides all the essential amino acids’
With plant sources, you are looking for three things:
A) signioficant amounts of all of the key Aminos
B) in roughly the correct ratios. There are plenty of plants with Met, for instance - but almost none of them have roughly half as much Met as Lys.
C) with enough protein overall that it can be considered a reasonable source on the first place.
Edamame is soy - probably the most animal-protein like of the common veg.
and yes, some of the "near grains" which remain staples in less developed countries generally fare better than the modern grains like corn and wheat. We (humans) spent a lot of time increasing the size of the grain to something easier to harvest, and lost some things along the way.