Test credit card numbers for test mode integration

Here is a list of sample/dummy/test credit card numbers, which are safe to use when you test credit card functionality on a website or application that involves credit card transactions. These credit card numbers validate properly but they are not actually in use.
American Express:
378282246310005
3111111111111117
343434343434343
370000000000002
340000000000009
371449635398431
378734493671000
Visa:
4111111111111111
4007000000027
4222222222222
4012888888881881
MasterCard:
5105105105105100
5111111111111118
5454545454545454
5500000000000004
5555555555551111
5555555555554444
Discover:
6011111111111117
6011000000000004
6011000990139424
6011601160116611
6111111111111116