I like Vegan in 7 by Rita Serano. It uses 7 ingredients or less and most have no oil and no salt or easily adapted to no salt. Plenty of bean recipes too. I also like Much More Veg by Hugh Fearnley Whittingstale, only suns are salt and oil and that hasn’t made a difference to the result, everything we’ve tried has been excellent.
The one that’s helped me most is The McDougall Quick and Easy Cookbook. Mainly because my friend (he is vegan) is a very picky eater who doesn’t like dishes with tons of ingredients. Since it’s for busy people who don’t like lots of prep I find he accepts more of what’s in there.