I recently learned that the symbol 〼, called 枡記号【ますきごう】, can be used as a phonetic shorthand for ます, as in 豆腐あり[〼]【ます】. In a similar vein, I am aware that 〆 is used as a shorthand for しめ in 〆切【しめきり】 = 締め切り, and sometimes in other words.
What other phonetic shorthands should a reader of Japanese be aware of? (Or, is there a word I can use to describe all of these things so I can look them up myself? 記号 is too broad, since it includes all kinds of symbols, and I don't know of any more specific word.) For the purposes of this question, let us ignore 略字, which I'm led to understand are fairly numerous.
If there are a lot of them, feel free to close as "too broad", but I imagine there can't be that many of them.