diff --git a/README.md b/README.md
index eff5426..12b0310 100644
--- a/README.md
+++ b/README.md
@@ -8,43 +8,52 @@ A curated list of awesome R packages and tools. Inspired by [awesome-machine-lea
 for <a target="_blank" href="https://github.com/rstudio/RStartHere/blob/master/top_downloads_2016/top_packages">Top 50</a> CRAN downloaded packages or repos with 400+
 <img class="emoji" alt="star" src="https://cdn.jsdelivr.net/gh/qinwf/awesome-R@3c66da6e291bcc0520b1649125b0bed750896a9a/star.png" height="20" align="absmiddle" width="20"></p>
 
-- [Awesome R](#awesome-)
-    - [2023](#2023)
-    - [2020](#2020)
-    - [2019](#2019)
-    - [2018](#2018)
-    - [Integrated Development Environments](#integrated-development-environments)
-    - [Syntax](#syntax)
-    - [Data Manipulation](#data-manipulation)
-    - [Graphic Displays](#graphic-displays)
-    - [Html Widgets](#html-widgets)
-    - [Reproducible Research](#reproducible-research)
-    - [Web Technologies and Services](#web-technologies-and-services)
-    - [Parallel Computing](#parallel-computing)
-    - [High Performance](#high-performance)
-    - [Language API](#language-api)
-    - [Database Management](#database-management)
-    - [Machine Learning](#machine-learning)
-    - [Natural Language Processing](#natural-language-processing)
-    - [Bayesian](#bayesian)
-    - [Optimization](#optimization)
-    - [Finance](#finance)
-    - [Bioinformatics and Biostatistics](#bioinformatics-and-biostatistics)
-    - [Network Analysis](#network-analysis)
-    - [Spatial](#spatial)
-    - [R Development](#r-development)
-    - [Logging](#logging)
-    - [Data Packages](#data-packages)
-    - [Other Tools](#other-tools)
-    - [Other Interpreters](#other-interpreters)
-    - [Learning R](#learning-r)
+- [Awesome R](#awesome-r)
+  - [2023](#2023)
+  - [2020](#2020)
+  - [2019](#2019)
+  - [Integrated Development Environments](#integrated-development-environments)
+  - [Syntax](#syntax)
+  - [Data Manipulation](#data-manipulation)
+  - [Data Formats](#data-formats)
+  - [Graphic Displays](#graphic-displays)
+  - [HTML Widgets](#html-widgets)
+  - [Reproducible Research](#reproducible-research)
+  - [Web Technologies and Services](#web-technologies-and-services)
+  - [Parallel Computing](#parallel-computing)
+  - [High Performance](#high-performance)
+  - [Language API](#language-api)
+  - [Database Management](#database-management)
+  - [Machine Learning](#machine-learning)
+  - [Natural Language Processing](#natural-language-processing)
+  - [Bayesian](#bayesian)
+  - [Optimization](#optimization)
+  - [Finance](#finance)
+  - [Bioinformatics and Biostatistics](#bioinformatics-and-biostatistics)
+  - [Network Analysis](#network-analysis)
+  - [Spatial](#spatial)
+  - [R Development](#r-development)
+  - [Logging](#logging)
+  - [Data Packages](#data-packages)
+  - [Other Tools](#other-tools)
+  - [Other Interpreters](#other-interpreters)
+  - [Learning R](#learning-r)
 - [Resources](#resources)
-    - [Websites](#websites)
-    - [Books](#books)
-    - [Podcasts](#podcasts)
-    - [Reference Cards](#reference-cards)
-    - [MOOCs](#moocs)
-    - [Lists](#lists)
+  - [Websites](#websites)
+    - [Manuals](#manuals)
+    - [Tools and References](#tools-and-references)
+    - [News and Info](#news-and-info)
+  - [Books](#books)
+    - [Free and Online](#free-and-online)
+    - [Paid](#paid)
+    - [Book/monograph Lists and Reviews](#bookmonograph-lists-and-reviews)
+  - [Podcasts](#podcasts)
+  - [Reference Cards](#reference-cards)
+  - [MOOCs](#moocs)
+  - [Lists](#lists)
+  - [R Ecosystems](#r-ecosystems)
+  - [2018](#2018)
+  - [2017](#2017)
 - [Other Awesome Lists](#other-awesome-lists)
 - [Contributing](#contributing)
 
@@ -248,6 +257,7 @@ for <a target="_blank" href="https://github.com/rstudio/RStartHere/blob/master/t
 * [Rcpp11](https://github.com/Rcpp11/Rcpp11) - Rcpp11 is a complete redesign of Rcpp, targetting C++11.
 * [compiler](http://stat.ethz.ch/R-manual/R-devel/library/compiler/html/compile.html) - speeding up your R code using the JIT
 * [cpp11](https://github.com/r-lib/cpp11) - cpp11 is a header-only R package that helps R package developers handle R objects with C++ code. It's similar to Rcpp but with different design trade-offs and features.
+* [Extendr](https://github.com/extendr) - Author high performance packages and functions in Rust, a modern alternative to C++ with nearly 200,000 libraries online.
 
 ## Language API
 *Packages for other languages.*