Quoted from snyper2099:Elektra is it but it is pre-alpha-numeric. Look up the ruleset... I wrote a 15 paragraph explanation of the rules once and it is NOT complete. As others have said, "deep or complex" does not always equate to "good". Elektra is not just deep, it is very specific. Not for the faint of reading.
Also an early one not yet mentioned is Williams Defender.
Elektra is amazing, IMO.