From: https://github.com/robbyrussell/oh-my-zsh/blob/master/lib/completion.zsh

completion.zsh

# fixme - the load process here seems a bit bizarre
zmodload -i zsh/complist

WORDCHARS=''

unsetopt menu_complete   # do not autoselect the first completion entry
unsetopt flowcontrol
setopt auto_menu         # show completion menu on successive tab press
setopt complete_in_word
setopt always_to_end

# should this be in keybindings?
bindkey -M menuselect '^o' accept-and-infer-next-history
zstyle ':completion:*:*:*:*:*' menu select

# case insensitive (all), partial-word and substring completion
if [[ "$CASE_SENSITIVE" = true ]]; then
  zstyle ':completion:*' matcher-list 'r:|=*' 'l:|=* r:|=*'
else
  if [[ "$HYPHEN_INSENSITIVE" = true ]]; then
    zstyle ':completion:*' matcher-list 'm:{a-zA-Z-_}={A-Za-z_-}' 'r:|=*' 'l:|=* r:|=*'
  else
    zstyle ':completion:*' matcher-list 'm:{a-zA-Z}={A-Za-z}' 'r:|=*' 'l:|=* r:|=*'
  fi
fi
unset CASE_SENSITIVE HYPHEN_INSENSITIVE

zstyle ':completion:*' list-colors ''
zstyle ':completion:*:*:kill:*:processes' list-colors '=(#b) #([0-9]#) ([0-9a-z-]#)*=01;34=0=01'

if [[ "$OSTYPE" = solaris* ]]; then
  zstyle ':completion:*:*:*:*:processes' command "ps -u $USER -o pid,user,comm"
else
  zstyle ':completion:*:*:*:*:processes' command "ps -u $USER -o pid,user,comm -w -w"
fi

# disable named-directories autocompletion
zstyle ':completion:*:cd:*' tag-order local-directories directory-stack path-directories

# Use caching so that commands like apt and dpkg complete are useable
zstyle ':completion::complete:*' use-cache 1
zstyle ':completion::complete:*' cache-path $ZSH_CACHE_DIR

# Don't complete uninteresting users
zstyle ':completion:*:*:*:users' ignored-patterns \
        adm amanda apache at avahi avahi-autoipd beaglidx bin cacti canna \
        clamav daemon dbus distcache dnsmasq dovecot fax ftp games gdm \
        gkrellmd gopher hacluster haldaemon halt hsqldb ident junkbust kdm \
        ldap lp mail mailman mailnull man messagebus  mldonkey mysql nagios \
        named netdump news nfsnobody nobody nscd ntp nut nx obsrun openvpn \
        operator pcap polkitd postfix postgres privoxy pulse pvm quagga radvd \
        rpc rpcuser rpm rtkit scard shutdown squid sshd statd svn sync tftp \
        usbmux uucp vcsa wwwrun xfs '_*'

# ... unless we really want to.
zstyle '*' single-ignored show

if [[ $COMPLETION_WAITING_DOTS = true ]]; then
  expand-or-complete-with-dots() {
    # toggle line-wrapping off and back on again
    [[ -n "$terminfo[rmam]" && -n "$terminfo[smam]" ]] && echoti rmam
    print -Pn "%{%F{red}......%f%}"
    [[ -n "$terminfo[rmam]" && -n "$terminfo[smam]" ]] && echoti smam

    zle expand-or-complete
    zle redisplay
  }
  zle -N expand-or-complete-with-dots
  bindkey "^I" expand-or-complete-with-dots
fi

history.zsh

## Command history configuration
if [ -z "$HISTFILE" ]; then
    HISTFILE=$HOME/.zsh_history
fi

HISTSIZE=10000
SAVEHIST=10000

# Show history
case $HIST_STAMPS in
  "mm/dd/yyyy") alias history='fc -fl 1' ;;
  "dd.mm.yyyy") alias history='fc -El 1' ;;
  "yyyy-mm-dd") alias history='fc -il 1' ;;
  *) alias history='fc -l 1' ;;
esac

setopt append_history
setopt extended_history
setopt hist_expire_dups_first
setopt hist_ignore_dups # ignore duplication command history list
setopt hist_ignore_space
setopt hist_verify
setopt inc_append_history
setopt share_history # share command history data

spectrum.zsh

#! /bin/zsh
# A script to make using 256 colors in zsh less painful.
# P.C. Shyamshankar <sykora@lucentbeing.com>
# Copied from http://github.com/sykora/etc/blob/master/zsh/functions/spectrum/

typeset -AHg FX FG BG

FX=(
    reset     "%{%}"
    bold      "%{%}" no-bold      "%{%}"
    italic    "%{%}" no-italic    "%{%}"
    underline "%{%}" no-underline "%{%}"
    blink     "%{%}" no-blink     "%{%}"
    reverse   "%{%}" no-reverse   "%{%}"
)

for color in {000..255}; do
    FG[$color]="%{[38;5;${color}m%}"
    BG[$color]="%{[48;5;${color}m%}"
done


ZSH_SPECTRUM_TEXT=${ZSH_SPECTRUM_TEXT:-Arma virumque cano Troiae qui primus ab oris}

# Show all 256 colors with color number
function spectrum_ls() {
  for code in {000..255}; do
    print -P -- "$code: %{$FG[$code]%}$ZSH_SPECTRUM_TEXT%{$reset_color%}"
  done
}

# Show all 256 colors where the background is set to specific color
function spectrum_bls() {
  for code in {000..255}; do
    print -P -- "$code: %{$BG[$code]%}$ZSH_SPECTRUM_TEXT%{$reset_color%}"
  done
}