Originally your PSU came with:
1x20+4pin mobo power connector
1x4 pin CPU power connector
1x8 pin CPU power connector
4x6 pin PCIe power connector
1x6+2 pin PCIe power connector
So, those connectors should be enough for all your hardware...
The question is if you bought the PSU separately as a brand new item or it was built in a system already?
If you bought it separately, then you should have all the cables...
If it came built in a system, then perhaps it didn't need all the cables so they were not provided... - in this case, since the PSU is modular, you should look for the individual cables on the Seasonic homepage or even ebay...