Horford will not be traded, but if he was on the market, any number of teams would make sense for various reasons.
Philly for Saric, Noel or Okafor, Illyasova, future 1st
Minny for Dieng, Lavine, Pekovic
Detroit for Harris, Morris
Utah with Smart for Favors, Hood, Burks
Chicago for Lopez, Gibson, 1st
Milwaukee with Smart for Parker, Monroe, Snell
I'm sure there are plenty of other potential trades