The obvious team is his old team in the Philadelphia Eagles, where he played nine seasons and made the Pro Bowl three times. During his time with the Eagles, Ertz was an elite tight end and had five straight seasons with 70 or more receptions and 800 or more receiving yards.
Towards the end of his time with the Eagles, he was splitting time with Dallas Goedert and Goedert has been the primary tight end over the past few seasons since the Ertz trade. The reason the Eagles could look to bring back Ertz is that Goedert is currently on injured reserve.
Goedert suffered a broken forearm fracture in Week 9 and according to NFL Network's James Palmer he is trying to play this weekend against the 49ers. However, the game against the Cowboys looks to be pretty realistic.
If the Eagles were to add Ertz, he knows the offense and should have no problem picking up where he left off. He likely will split reps with Goedert which could limit his fantasy football outlook but joining this offense is not a bad thing.