Where can I find a complete list of Bitcoin forks (soft, hard, intentional and unintentional) I was looking to study the history of Bitcoin forks including the 2013 incident that may or may not have been a Hard fork depending on your definition.
There is a paper that provides extensive detail on the history of all kind of forks on Bitocin, Ethereum and Ethereum Classic, you can read it here, Atomically Trading with Roger: Gambling on the success of a hardfork. 

Here is the list of Forks so far,



The following content is sourced from the above paper,


  So far, Bitcoin has implemented over six softforks. These softforks
  range from introducing rules to prevent miners creating coinbase
  transactions with duplicated identification hashes, requiring all
  ECDSA signatures to strictly enforce DER coding, and introducing both
  absolute and relative lock times for individual transaction outputs.
  In terms of implementation, this involves storing new information in
  the scriptsig of the coinbase transaction, constraining transaction
  validation rules or re-defining the use of special OP_NOP function. On
  the other hand, Bitcoin has experienced two accidental (and temporary)
  splits (i.e. Fork-1, Fork-2 emerged) that required miner intervention
  to remedy. The first split permitted a user to exploit an integer
  overflow bug and create 184 billion coins. This required miners to
  co-operatively extend a new blockchain without the coin creation
  transaction [6] and to enforce a soft-fork to prevent this exploit.
  The second split involved miners who upgraded to Bitcoin Core 0.8
  accidentally creating blocks that were invalid for Bitcoin Core 0.7.
  Unfortunately, BerkeleyDB’s configuration in Bitcoin Core 0.7 was
  non-deterministic and as a result was not compatible with LevelDB’s
  configuration in Bitcoin Core 0.8. Resolving this fork required miners
  to immediately downgrade to Bitcoin Core 0.7 and abandon the forked
  blockchain. Next, the developers released Bitcoin Core 8.1 that
  enforced the activation of a hardfork12 after a two-month grace period
  for miners and users to upgrade