Free Code Improvement Alternatives

I really liked using ReSharper (JetBrains) in Microsoft Visual Studio.

There are also some other commercial tools like it:
- CodeRush (DevExpress)
- JustCode (Telerik)

The functionality that I found most useful was:
- Go To Implementation
- Find Usages
- Suggestions on code improvements
- Extract function

I think that ReSharper has become too expensive now, currently at a $299 first year subscription, then a bit lower on subsequent years. That's about 40% of the price of Visual Studio Professional, and you don't even buy the product - you subscribe.

So I am testing out this combo as an alternative:

Roslyn provides the Light Bulb for code improvements:
https://blog.tommyparnell.com/vs-2015-getting-resharper-experiance-without-resharper/

Several very handy tools:
- Productivity Power Tools

For more code improvement suggestions (pick one, not both):
- CodeCracker for C# (testing this now, looks good)
- Refactoring Essentials for Visual Studio*

I have also tested CodeMaid, but not just right now*.
I may enable it again at a later point in time though.
It looks like a very useful addition to Visual Studio.

Here are some related Stack Overflow questions:
http://stackoverflow.com/questions/2834439/what-are-some-alternatives-to-resharper
http://stackoverflow.com/questions/24542406/alternatives-to-resharper

*Enabling too many competing plugins may cause VS to run very slowly.