The ICRC API currently only supports SNS and chain-key tokens. We will add support for non-SNS/ck tokens in the future, but I don’t have an ETA on that. Also see my post here.
As @jennifertran indicated, you can always call the token canisters directly, and optionally index the data yourself, especially if you’re building your own dashboard, as the ICRC API does for the ICP Dashboard.