Your .gradle folder keeps a copy of Gradle for every project

The Gradle wrapper is a good idea with a storage cost nobody mentions: each project pins the exact Gradle version it wants, and your Mac downloads and keeps a complete copy of every version any project has ever asked for.

What each folder is

du -sh ~/.gradle/* 2>/dev/null | sort -h
du -sh ~/.gradle/wrapper/dists/* 2>/dev/null | sort -h | tail

The wrapper distributions are the easy win

Each entry under wrapper/dists is a complete Gradle, roughly 100 to 200 MB unpacked. You need the versions your current projects pin, which is one line per project:

grep -rh distributionUrl ~/**/gradle/wrapper/gradle-wrapper.properties 2>/dev/null \
  | sort -u

Anything under dists that is not in that output belongs to a project you no longer have, or to a version you have since upgraded past. Removing it costs a download only if something asks for it again.

The daemon folder that only ever grows

Gradle keeps a background process between builds for speed, and it writes a log per daemon per version. Nothing rotates them. On the measured Mac this was 65 MB, which is not a crisis, but it is pure debris and it is safe to clear whenever no build is running.

./gradlew --stop        # from a project, stops running daemons
rm -rf ~/.gradle/daemon # then clear the logs

Doing it without breaking a build

1. Stop the daemons first, or the folder is rewritten while you look at it.
2. Clear daemon freely. It is logs.
3. Clear wrapper/dists for versions no project pins.
4. Clear caches/modules-2 last. It is the largest and the most annoying to rebuild, since it means redownloading every dependency.

Gradle is rarely alone on a Mac that has it. Android Studio's own folders cover the emulator images and SDK, which are usually larger again, and the Xcode side has the same shape if you build for both platforms.