Here are top 15 most popular Comments plugins for WordPress websites.
1. JetPack
wordpress.org
2. wpDiscuz
wordpress.org
3. Super Socializer
wordpress.org
4. Disqus Comment System
wordpress.org
5. WP First Letter Avatar
wordpress.org
6. CommentLuv
wordpress.org
7. Deeper Comments
wordpress.org
8. Subscribe To Comments Reloaded
wordpress.org
9. Simple Comment Editing
wordpress.org
10. Replyable
wordpress.org
11. GraphComment Comment system
wordpress.org
12. ReplyBox
wordpress.org
13. No Self Pings
wordpress.org
14. Lazy Load for Comments
wordpress.org
15. Disable Comments
wordpress.org