SHA-256 alternate cryptocurrencies
Alt coins using SHA-256, the same hashing algorithm as Bitcoin.
NMC – Namecoin
PPC – PPCoin (Peercoin)
DVC – Devcoin
TRC – Terracoin
BTE – Bytecoin
IXC – Ixcoin
I0C – I0coin
FRC – Freicoin
BLC – Blakecoin
Scrypt alternate cryptocurrencies
Alt coins using scrypt algorithm
LTC – Litecoin
NVC – Novacoin
FTC – FeatherCoin
MNC – MinCoin
BBQ – BBQcoin
TAG – Tagcoin
MEG – Memorycoin
BTCs/BTC2 – Bitcoin Scrypt
Alternate cryptocurrencies can be mined using the same hardware as for mining Bitcoins (mostly SHA-256 alt coins). While bitcoin mining is going to use FPGA and ASIC devices, scrypt based alt coins can be mined using GPU cards.
Other alternate cryptocurrencies
Alt coins using other, innovative hashing algorithms
XPM – Primecoin
QRK – Quark
SRC – Securecoin
Nxt – Next
SKN – Skeincoin
PTS – Protoshares
Curecoin
OFF – Offerings to Cthulhu
HTC – Huitongbi
PGC – Pangucoin