Say which carriers you represent
It is the clearest thing an independent agency can publish and most of them do not.
The independent agency argument is access to multiple markets. That claim is abstract until the carriers are named, at which point a visitor can evaluate it.
It also does practical work. Somebody with a preference, or somebody who has been declined by a particular carrier, is looking for exactly this information.
Carriers usually have requirements about how their names and logos may be used in agency advertising, so this is worth checking against your agreements rather than assuming.
Keep it accurate, since appointments change. A carrier listed that you can no longer place with produces an inquiry you have to decline.
For specialty markets in particular, naming access is a genuine differentiator, because a prospect who has been turned down elsewhere is searching specifically for somebody who has it.