diff --git a/zsh/aliases.zsh b/zsh/aliases.zsh
index 1a40d6f..99883bd 100644
--- a/zsh/aliases.zsh
+++ b/zsh/aliases.zsh
@@ -114,3 +114,11 @@ fi
 
 alias bytefmt2="numfmt --to=iec-i --suffix=B"
 alias bytefmt10="numfmt --to=si --suffix=B"
+
+if command_exists dragon-drag-and-drop && ! command_exists dragon; then
+  alias dragon='dragon-drag-and-drop'
+fi
+
+if gnu_time_path="$(command_locate time)" && [[ -n "$gnu_time_path" ]]; then
+  alias gtime="${(q)gnu_time_path} -v"
+fi
diff --git a/zsh/functions.zsh b/zsh/functions.zsh
index f378e7e..3a21626 100644
--- a/zsh/functions.zsh
+++ b/zsh/functions.zsh
@@ -26,7 +26,11 @@ viscd() {
   }
 }
 
-command_exists() { command -v "$1" &>/dev/null; }
+# Checks if a word can be meaningfully executed as a command (aliases,
+# functions and builtins also count).
+command_exists() { whence -- "$@" &>/dev/null; }
+# Searches the command binary in PATH.
+command_locate() { whence -p -- "$@"; }
 
 lazy_load() {
   local command="$1"
@@ -131,3 +135,14 @@ sync_working_dir_load() {
   fi
 }
 alias cds="sync_working_dir_load"
+
+discord-avatar() {
+  setopt local_options err_return
+  if (( $# != 1 )); then
+    print >&2 "Usage: $0 [user_snowflake]"
+    return 1
+  fi
+  local avatar_url
+  avatar_url="$(discord-whois --image-size 4096 --get 'Avatar' "$1")"
+  open "$avatar_url"
+}
diff --git a/zsh/plugins.zsh b/zsh/plugins.zsh
index 1472428..174551f 100644
--- a/zsh/plugins.zsh
+++ b/zsh/plugins.zsh
@@ -14,8 +14,7 @@ _plugin completions-rustc 'https://raw.githubusercontent.com/rust-lang/zsh-confi
 _plugin completions-cargo 'https://raw.githubusercontent.com/rust-lang/cargo/master/src/etc/_cargo' from=url \
   after_load='plugin-cfg-path fpath prepend ""'
 
-rustup_bin="${commands[rustup]}"
-if [[ -n "$rustup_bin" ]]; then
+if rustup_bin="$(command_locate rustup)" && [[ -n "$rustup_bin" ]]; then
   rustup_comp_path="${ZSH_CACHE_DIR}/site-functions/_rustup"
   if [[ "$rustup_bin" -nt "$rustup_comp_path" || ! -s "$rustup_comp_path" ]]; then
     _perf_timer_start "generate rustup completions"
@@ -23,7 +22,7 @@ if [[ -n "$rustup_bin" ]]; then
     _perf_timer_stop "generate rustup completions"
   fi
   unset rustup_comp_path
-fi
+fi; unset rustup_bin
 
 # compinit {{{
   _perf_timer_start "compinit"
@@ -146,4 +145,10 @@ if [[ "$TERM" != "linux" ]]; then
   fi
 fi
 
+if (( _is_macos )); then
+  plugin retina 'https://raw.githubusercontent.com/lunixbochs/meta/master/utils/retina/retina.m' from=url \
+    build='mkdir -p bin && gcc retina.m -framework Foundation -framework AppKit -o bin/retina' \
+    after_load='plugin-cfg-path path prepend "bin"'
+fi
+
 unset _checkout_latest_version