There are a lot of Easter Eggs that are spread throughout the corners of Lightning Returns: Final Fantasy XIII.
Few of them found so far are given below:
Biggs and Wedge
Repeated visits to Yusnaan reveals two mysterious strangers who act as gatekeepers to the Industrial Area passageways are in fact “Biggs and Wedge” traditional FF13 favorites making an appearance. However their faces are covered by masks and their identities are momentarily hidden.
Cid makes a little appearance as a manifestation of The Chaos, a singular personified embodiment of the tortured souls who appeals to Lightning near the game’s ending.
Moogles are a race of puffy hovering creatures common to most games in the Final Fantasy series. They appear in a hiddle village in the Wildlands. Among the Moogles is FF13-2 protagonist Mog.