I am looking for character which could replace image icon, for example like ✘ (xmark) and ✔ (tick), maybe some symbol to \"draft\" or \"new message\"?
EDIT:
Look at http://unicode.org/charts#symbols for some ideas. I'm not sure what would work for "draft" or "new message" but there is a lot to choose from there.
I would suggest using custom font like https://github.com/FortAwesome/Font-Awesome
You can also have svg/png version https://github.com/encharm/Font-Awesome-SVG-PNG
There are also other svg icons
For Material Design you have static svg icons https://google.github.io/material-design-icons/ and animated:
stackoverflow.com used to use "●" (U+25CF BLACK CIRCLE) for badges.
There are tons of useful characters in Unicode:
← ↑ → ↓ ↔ ↕ ↖ ↗ ↘ ↙
just to name a few...
I am surprised no one has posted Unicode emojis yet:
Range U+1F600 - U+1F64F
Just some from the list:
Why not just peruse the whole list?