...
github.com/gogo/protobuf
github.com/jackc/pg*
golang.org/x/*
google.golang.org/*github.com/golang/*grpc
go.etcd.io/etcd/raft (now go.etcd.io/raft)
cloud.google.com/*
github.com/Azure/*
github.com/aws/*
golang.org/x/* packages are maintained and curated by the go project, just without the backwards compatibility promises the standard library makes, and should be treated like part of the go standard library. Accordingly upgrades to golang.org/x packages are treated similarly to go upgrades: they’re considered sweeping changes, are avoided in backports, and following the merge of such changes we should communicate to all teams to be on the lookout for behavior changes, just like we would after a go upgrade.