IPASKPeeringDB
A self-declared registry of networks: type, peering policy, facilities.
PeeringDB is where network operators describe themselves: ASN, name, network type, peering policy and the internet exchanges they join.
The info_type field is the useful part for IP checks: Cable/DSL/ISP, NSP, Content, Enterprise, Educational/Research, Government. It helps refine a verdict when the ASN name alone is ambiguous.
Because it is self-declared, small networks may be missing. Use it to refine, never to overrule a stronger signal.
Related: Residential IP · Native IP · Dual ISP · CGNAT · ASN · BGP · RPKI · Anycast