There is for sure the bulk of Golani brigade. As for equipment, you may check
www.tank-net.org, AFV section has a nice thread with pics from Gaza - mostly Achzarits from the last few days. Also plenty of Merkavas seen were MkII or III (uparmored), relatively few MkIV - my guess is that MkIV is seen as "unneccessary" for gaza and is reserved for the case Hezbollah wakes up in the North.
Among the photos of troops gathering for the ground op there was even atleast a company of Mag'ach 7C, presumably reserve unit.