Signify (Philips) eliminated effects from its new API. That’s why they no longer exist in the new Philips Hue integration (which employs the new API).
FWIW, there’s an effect that makes a light “breathe” (what you see when the Hue app identifies a light for configuration) and the developer intends to use that for a long flash (there’s nothing natively available to support a short flash).