What Cargo addons do you use?

Cargo comes with quite a lot of nifty things pre-packaged, like fmt, clippy and so on. But there are a lot of addons out there, and it is a bit hard to discover these, so I thought it would be interesting to hear what everybody is using. The things I have installed is:

• cargo-outdated - Find outdated dependencies
• cargo-udeps - Find unused dependencies
• cargo-flamegraph - Performance analysis
• cargo-about - I use it to list licenses

Of these, it is cargo-outdated I use frequently. So, what is your cargo addon you cannot live without.