No, NVIDIA cards DO NOT come with a SLI bridge. Only SLI Capable motherboards come with SLI bridge. Now, All radeon cards that support Crossfire do some with a Crossfire ribbon cable. And some crossfire capable motherboards come with a crossfire cable. But most of the time its SLI cables come with motherboards and crossfire cables come with Radeon cards
Realized that my Gigabyte mother board with AMD chip only supports Crossfire; so I am returning all video cards and have ordered two ASUS HD7970-DC2-3GD5 AMD Radeon HD 7970 Video Card - 3GB, GDDR5, AMD Radeon HD 7970, PCI Express 3.0, DVI, Display Port, 1x HDMI, DirectX 11 cards with crossfire bridge. Sometimes it really pays to spec things out properly before ordering. I am almost 68 and just built my first PC from the ground up using a Gigabyte GA-970A-D3 mother board with an AMD Phenom II X4 970 Black Edition CPU with a Noctua NH-D14 SE2011 Quiet CPU Cooler.