StyleFill: Custom Styles for Google Docs™

StyleFill is an add-on for Google Docs™ that gives you your own paragraph and character styles. Make one from text formatted the way you want, apply it from the sidebar, and change it later: every place it was applied in the document is updated. Your styles are kept with your Google account, so every document you open has them.

Make a style from your text: select a paragraph or some words, name the style, and StyleFill takes their font, size, colors, bold, italic, underline and strikethrough. A paragraph style also takes the alignment, line spacing, space above and below, indents and outline level.
Apply it from the sidebar: a paragraph style to the paragraphs you select, a character style to the selected words.
Change it, update everywhere: edit a style’s settings or take them again from the selection, and every place it was applied is updated, in every tab of the document. In your other documents, open StyleFill and click Update.
In every document: your styles go with your Google account, not with one document.
Share a set: export your styles as a small text file, and import a set from a colleague.

Good to know. Text you copy, cut and paste, or paste in from another document, drops out of its style: Update does not reach it, so apply the style to it again. Press Enter inside a paragraph with a paragraph style and only the first part keeps the style. Text typed at the very start of a paragraph, before styled words, stays out of their style. Text added right after styled words that looks exactly like them joins them at the next update. Docs’ own Styles menu lists only Docs’ styles, so StyleFill’s are applied from its sidebar. Paragraph borders are not part of a style.

Plans

Free: 2 styles in total per Google account, made or imported. Deleting a style does not give it back. Applying, editing and updating styles are always free.
StyleFill: $9 once per Google account for unlimited styles. No subscription. Refunds within 14 days. See the terms.

Open it from Extensions > StyleFill in any document.

Add-on will not open or uses the wrong Google account?