Add more badges

Author: wooorm

readme.md

@@ -3,6 +3,9 @@
 [![Build][build-badge]][build]
 [![Coverage][coverage-badge]][coverage]
 [![Downloads][downloads-badge]][downloads]
+[![Size][size-badge]][size]
+[![Sponsors][sponsors-badge]][collective]
+[![Backers][backers-badge]][collective]
 [![Chat][chat-badge]][chat]
 
 Get the style of [**mdast**][mdast] headings.
@@ -72,9 +75,19 @@ repository, organisation, or community you agree to abide by its terms.
 
 [downloads]: https://www.npmjs.com/package/mdast-util-heading-style
 
+[size-badge]: https://img.shields.io/bundlephobia/minzip/mdast-util-heading-style.svg
+
+[size]: https://bundlephobia.com/result?p=mdast-util-heading-style
+
+[sponsors-badge]: https://opencollective.com/unified/sponsors/badge.svg
+
+[backers-badge]: https://opencollective.com/unified/backers/badge.svg
+
+[collective]: https://opencollective.com/unified
+
 [chat-badge]: https://img.shields.io/badge/join%20the%20community-on%20spectrum-7b16ff.svg
 
-[chat]: https://spectrum.chat/unified/remark
+[chat]: https://spectrum.chat/unified/syntax-tree
 
 [license]: license