Affiliated Chains are projects that team up with Ankr AppChains, using it as part of their infrastructure. For example, BNB Sidechain is almost entirely implemented using AppChains and thus is a paragon of the power AppChains can offer. It's a complex project that you can build upon and especially useful if your company is new to Web3 and wants a whole setup. Other example is Polygon Superset's — a partner that takes from AppChains what it misses, e.g., trusted validators for its validators set.