Org Mode plain lists uses the hyphen (minus sign) character as it’s default bullet. The hyphen is pretty wimpy compared to the Asterisk character so it can be hard to read. Here is some code to visualize it with an Em-Dash instead—so much easier to read!
(font-lock-add-keywords 'org-mode '(("^[[:space:]]*\\(-\\) " 0 (prog1 () (compose-region (match-beginning 1) (match-end 1) "—")))))
Hyphen on the left and em-dash on the right
Via jessicastringham via howardism. I made two changes: first don’t work on headline bullets and second match the first list bullet because it didn’t on my system.
You can use that code for any character not just em-dash