One of the most frequent questions I am asked as a 30+ year vegetarian is where do you get your protein? There seems to be a belief that the only source of protein is meat.
What are the highest sources of protein for vegetarians and for vegans?
As long as you aren't eating the same food every meal, you will get enough protein on a vegan diet. Vegetables, potatoes, rice, grains, beans, nuts, seeds, and soy etc. all contain plenty of protein. Some are defficient in one or two amino acids that the others contain, so as long as you eat different things throughout the week you will get enough protein to meet your daily requirements in every amino acid. Note you do not have to mix foods at meals, just have to mix them up throughout the week.
That said here is a list of foods ranked by percent of their calories being protein (note its a bit of a random selection)
Food / % cals protein / g protein per GBP (British pound sterling)
The data and chart come from this Google spread sheet.
This will not be a comprehensive answer and is intended to kick-start what might end up as part of a FAQ.
Most pulses (the seeds from legumes) e.g. lentils, are a good protein source and are also versatile meal ingredients.
Nuts have high levels of proteins.
Soy is a seed that can be made into tofu or a cow milk substitute.
Have a look at this site (no affiliation) for a good list with explanations and recipes. http://greatist.com/health/complete-vegetarian-proteins
Personally I tend to eat Quorn products, which are made from mycoprotein, which is a kind of fungal protein. It's fermented in vats and fed with glucose syrup, so it's entirely fungus and plant based. Interestingly it also doubles its mass in 5 hours, so it's a fairly efficient substance too.
Note that some mycoprotein products might not be suitable for vegans because they may contain free-range eggs, but in recent years more vegan variations have been introduced.
As for the protein content, it has more protein per mass than beef, and it has a reasonably high fibre content.
I have been a vegetarian all my life. Recently I started to do some dieting to lose weight, and I have cut down on carbs a whole lot. So, I'm always looking for protein sources to incorporate in my diet. And this is what I eat.
I hope you find these helpful.