The ASRock Fatal1ty H97 Killer comes with one PCI Express 3.0 x16 slot, one PCI Express 2.0 x16 slot (working at x4 speed), two PCI Express 2.0 x1 slots, and two PCI slots.
Only the first PCI Express x16 slot is controlled by the CPU, so it is based on the 3.0 specification and does not share bandwidth with other slots, i.e. it always works at x16 speed. On the other hand, the second PCI Express x16 slot is controlled by the chipset (so it is based on the 2.0 specification) and shares bandwidth with the PCI Express 2.0 x1 slots: if one of them is used, the second PCI Express x16 slot works only at x2 speed, not x4.
The motherboard supports CrossFireX, but not SLI.
There is also an M.2 slot, supporting one SATA-600 or PCI Express x2 SSD module.