~ followed by a number is often used to mean approximately that number. eg: "we're expecting ~100 people". You are also using it for strikethrough formatting.
Looking at my keyboard the least ambiguous/overused symbol is probably the & - but I'm not sure if that's better overall.replied to a while ago:
That works nicely. Although again you will get unintentional usage because
replied to:Let’s usetildeampersand, check .