I wish there was an agreed upon way to extend fonts with icons. For example I found https://github.com/ryanoasis/vim-devicons which adds icons to Nerdtree (on the terminal) by leveraging nerdfonts (https://nerdfonts.com).

There also is awesome-terminal-fonts (https://github.com/gabrielelana/awesome-terminal-fonts). I feel if this was somehow standardized we would see much more vim and emacs plugins and cli tools support icons in the terminal.