Coin Mixing
Stablecoin (in progress)
FedoraCoin (complete)
CoinJoin
Darkcoin (in progress)
zero-knowledge proofs
zerocoin (in progress)
transferring coins using the darknets only
anoncoin (complete)
I thought anoncoin was working on implementing zerocoin, and still a month away from completion.
Also, why do you think darkcoin has been so well received, but Fedoracoin (Tips) has yet to see a price bump even though they are the 1st to introduce truly anonymous transactions.