Start with the same category and recorded primary feature, then narrow by the features you need. These are discovery candidates, not a claim that every product replaces every feature.
Verified alternatives
Each one checked against Veil: White Noise Sleep Sounds: it does the same main job for a similar customer, so a buyer could choose it instead.
Slo is a sound app and browser-based mixer offering brown, white, pink, and green noise plus nature sounds like rain and ocean waves. It supports layering sounds with individual volume controls and includes a sleep timer that fades sounds out gently.
NeuroSet is an iOS app that plays binaural beats, pure tones, solfeggio frequencies, and guided breathing exercises as timed sets for focus, energy, calm, and sleep. It synthesizes audio live on the iPhone and offers a daily habit structure with streaks, scheduling, and reminders without requiring an account.