I'm surprised that pickled onions didn't get a mention.
A standard pickled recipe looks a lot like the onion juice ingredients: onions, vinegar, salt - but commonly includes some sugar (I suspect this is historically a recent addition, given the age of this preserving method and the scarcity of sugar more than a century ago).
Pickled onions (and eggs, herrings, etc) are commonly seen in British pubs - scooped out and sold by the unit as a salty comestible in the age old tradition of making your customers thirstier.
A standard pickled recipe looks a lot like the onion juice ingredients: onions, vinegar, salt - but commonly includes some sugar (I suspect this is historically a recent addition, given the age of this preserving method and the scarcity of sugar more than a century ago).
Pickled onions (and eggs, herrings, etc) are commonly seen in British pubs - scooped out and sold by the unit as a salty comestible in the age old tradition of making your customers thirstier.