1.Google

1.Google

https://github.com/google

2.Google Samples

https://github.com/googlesamples

3.Google Codelabs

https://github.com/googlecode…

4.GoogleChrome

https://github.com/GoogleChrome

5.Google Creative Lab

https://github.com/googlecrea…

6.Google Internationalization

人人皆可使用的Google开源字体

https://github.com/googlei18n

7.tensorflow

https://github.com/tensorflow

2.Facebook

1.Facebook

https://github.com/facebook

2.Facebook Samples

https://github.com/fbsamples

3.facebookresearch

https://github.com/facebookre…

4.Facebook Incubator

https://github.com/facebookin…

3.Twitter, Inc.
https://github.com/twitter
4.Square（android开源的类库多而且厉害）
https://github.com/square
5.Alibaba

1.
https://github.com/alibaba

2.hiloteam(阿里，终端跨平台小游戏)

https://github.com/hiloteam

https://github.com/hiloteam/hilo

3.ant-design(一套企业级的 UI 设计语言和 React 实现)

https://github.com/ant-design

6.Kotlin（可以写Android,现在已经扶正了）
https://github.com/Kotlin
7.ReactiveX（函数响应式编程）
https://github.com/ReactiveX
https://github.com/Reactive-E…
8.Airbnb
https://github.com/airbnb
9.Apple
https://github.com/apple
10.Uber
https://github.com/uber
11.百度

1.Baidu EFE team

https://github.com/ecomfe

2.baidu-research

https://github.com/baidu-rese…

3.echarts

https://github.com/apache/inc…

12.Bilibili（B站）
https://github.com/Bilibili
13.Yalantis（音乐播放，好多比较好的移动端效果）
https://github.com/Yalantis
https://yalantis.com/
14.Spring
https://github.com/spring-pro…
15.饿了么
https://github.com/eleme
https://elelogistics.github.io/
16.腾讯相关

1.腾讯

https://github.com/Tencent

2.腾讯前端库

https://github.com/AlloyTeam

3.微信开发团队

https://github.com/WeMobileDe…

17.Yalantis（好几个效果不错android的控件）
https://github.com/Yalantis
18.SwiftAndroid
https://github.com/SwiftAndroid
19.Ramotion（App Development Agency | Available for new projects）
https://github.com/Ramotion
20.Tinify(压缩图片的那个网站)
https://github.com/tinify
21.豆瓣
https://github.com/douban
22.WeUI（微信ui）
https://github.com/weui
23.美团·大众点评
https://github.com/Meituan-Di…
24.极光开发者
https://github.com/jpush
25.Dropbox
https://github.com/dropbox
26.伯乐在线
https://github.com/jobbole
27.grpc（gRPC：Google开源的基于HTTP/2和ProtoBuf的通用RPC框架）
https://github.com/grpc
28.Nike Inc.(耐克)
https://github.com/Nike-Inc
29.Medium
https://github.com/Medium
30.Microsoft
https://github.com/Microsoft
31.Mapbox
https://github.com/mapbox
32.JetBrains(好多ide都是他家出的)
https://github.com/JetBrains
33.滴滴出行
https://github.com/didi
34.华为

1.主团队

https://github.com/Huawei

2.大数据团队

https://github.com/HuaweiBigData

35.小米
https://github.com/xiaomi
36.知乎
https://github.com/zhihu
37.vue
https://github.com/vuejs
38.iView
https://github.com/iview
39.Node
https://github.com/nodejs
40.Fuchsia
https://github.com/fuchsia-mi…
41.Flutter
https://github.com/flutter
42.Apache
https://github.com/apache
43.AMAP-Demo(高德开放平台示例中心)
https://github.com/amap-demo
44.GitHub
https://github.com/github

持续更新,排名不分先后。。。
欢迎大家补充