以下のコマンドを実行すると、HomebrewでインストールしたFomulaの容量を知ることができます。
コマンド
brew leaves | xargs brew info | grep '*'
実行結果
/usr/local/Cellar/asciinema/1.3.0 (29 files, 78.0K) *
/usr/local/Cellar/carthage/0.18 (48 files, 12.2M) *
/usr/local/Cellar/clojurescript/1.9.76 (3 files, 21.4M) *
/usr/local/Cellar/colordiff/1.0.16 (8 files, 54.4K) *
/usr/local/Cellar/crystal-lang/0.19.2 (650 files, 41.3M) *
/usr/local/Cellar/dhcping/1.2 (5 files, 30K) *
/usr/local/Cellar/dinghy/4.4.1 (177 files, 487.9K) *
/usr/local/Cellar/dnsmasq/2.76 (7 files, 504.5K) *
/usr/local/Cellar/elasticsearch/2.4.0 (59 files, 29.1M) *
/usr/local/Cellar/elixir/1.3.3 (383 files, 5M) *
/usr/local/Cellar/emacs-plus/25.1 (4,045 files, 120.2M) *
/usr/local/Cellar/erlang/19.0.2_1 (7,292 files, 278.7M) *
/usr/local/Cellar/faac/1.28 (15 files, 685.5K) *
/usr/local/Cellar/ffmpeg/3.1.3 (236 files, 51.6M) *
/usr/local/Cellar/fish/2.3.1 (786 files, 5.9M) *
/usr/local/Cellar/flow/0.32.0 (7 files, 4.8M) *
/usr/local/Cellar/gcsfuse/0.19.0 (5 files, 14.6M) *
/usr/local/Cellar/gibo/1.0.4 (5 files, 9K) *
/usr/local/Cellar/git/2.10.0 (1,432 files, 31.7M) *
/usr/local/Cellar/git-lfs/1.4.1 (5 files, 9.3M) *
/usr/local/Cellar/git-secret/0.1.1 (27 files, 36.4K) *
/usr/local/Cellar/gnupg/1.4.21 (57 files, 5.4M) *
/usr/local/Cellar/gnupg2/2.0.30_2 (91 files, 3.7M) *
/usr/local/Cellar/gradle/3.1 (173 files, 73M) *
/usr/local/Cellar/graphicsmagick/1.3.25 (476 files, 11.9M) *
/usr/local/Cellar/graphviz/2.38.0_1 (506 files, 67.0M) *
/usr/local/Cellar/gtk+/2.24.31 (1,198 files, 53.0M) *
/usr/local/Cellar/highlight/3.31 (347 files, 2.4M) *
/usr/local/Cellar/htop-osx/0.8.2.8 (11 files, 148.3K) *
/usr/local/Cellar/hub/2.2.8 (9 files, 9M) *
/usr/local/Cellar/hugo/0.16 (29 files, 17.6M) *
/usr/local/Cellar/iproute2mac/1.1.1 (5 files, 18.8K) *
/usr/local/Cellar/jq/1.5_2 (18 files, 958K) *
/usr/local/Cellar/kibana/4.5.1 (14,674 files, 125.7M) *
/usr/local/Cellar/kotlin/1.0.3 (23 files, 23.6M) *
/usr/local/Cellar/leiningen/2.7.0 (8 files, 14.7M) *
/usr/local/Cellar/logstash/2.4.0 (10,197 files, 137.3M) *
/usr/local/Cellar/lynx/2.8.8rel.2_1 (10 files, 2.2M) *
/usr/local/Cellar/maven/3.3.9 (94 files, 9.6M) *
/usr/local/Cellar/mdp/1.0.8 (7 files, 86K) *
/usr/local/Cellar/memcached/1.4.24 (10 files, 162K) *
/usr/local/Cellar/mercurial/3.9.1 (427 files, 5.8M) *
/usr/local/Cellar/mongodb/3.2.9 (17 files, 241.2M) *
/usr/local/Cellar/mono/4.6.0.245 (1,599 files, 232.2M) *
/usr/local/Cellar/most/5.0.0a (13 files, 136.7K) *
/usr/local/Cellar/nkf/2.1.4 (4 files, 342.5K) *
/usr/local/Cellar/numpy/1.11.1 (430 files, 9M) *
/usr/local/Cellar/nvm/0.32.0 (6 files, 115.7K) *
/usr/local/Cellar/ondir/0.2.3 (8 files, 47.3K) *
/usr/local/Cellar/pandoc/1.17.2 (72 files, 84.8M) *
/usr/local/Cellar/peco/0.4.2 (5 files, 4.2M) *
/usr/local/Cellar/postgresql/9.5.4 (3,147 files, 35M) *
/usr/local/Cellar/python3/3.5.2_1 (3,494 files, 53.2M) *
/usr/local/Cellar/qiitactl/v0.1.3 (4 files, 10.1M) *
/usr/local/Cellar/reattach-to-user-namespace/2.5 (6 files, 34K) *
/usr/local/Cellar/redis/3.2.3 (10 files, 1.7M) *
/usr/local/Cellar/rust/1.11.0 (12,344 files, 255.3M) *
/usr/local/Cellar/siege/4.0.2 (15 files, 285.9K) *
/usr/local/Cellar/spidermonkey/1.8.5_1 (103 files, 10.6M) *
/usr/local/Cellar/ssh-copy-id/7.3p1 (7 files, 308.3K) *
/usr/local/Cellar/suite-sparse/4.5.3 (344 files, 17.2M) *
/usr/local/Cellar/thrift/0.9.3 (94 files, 5.3M) *
/usr/local/Cellar/tig/2.2 (11 files, 447.9K) *
/usr/local/Cellar/tmux/2.2 (9 files, 639.7K) *
/usr/local/Cellar/tree/1.7.0 (7 files, 113.1K) *
/usr/local/Cellar/unar/1.10.1 (77 files, 13.6M) *
/usr/local/Cellar/unixodbc/2.3.4 (39 files, 952.3K) *
/usr/local/Cellar/watchman/HEAD (26 files, 690.3K) *
/usr/local/Cellar/wercker-cli/1.0.560 (2 files, 20.4M) *
/usr/local/Cellar/wget/1.18 (9 files, 1.6M) *
/usr/local/Cellar/wrk/4.0.2 (6 files, 2.3M) *
補足
brew leaves は他のFomulaに依存しないFomulaの一覧を表示するコマンドです。brew leavesで取得したFomula一覧に対して、brew infoで詳細を表示し、grep を使ってFomulaのサイズを表示している行のみ絞り込んでいます。