Conditionally licensed sfx models
1 in the catalogue today, and the list grows as the market does. Every one with what it costs, who sells it and where it stands.
Models that make a sound rather than music or speech: a door, rain, an engine, a room tone. They are bought by the clip, they are short, and the thing to check is whether the licence lets the sound into something you sell.
Weights you can download, under a licence that asks for something in return: an acceptable-use policy, a naming requirement, a revenue ceiling above which you must ask, a restriction on training other models. The Llama and Gemma families are the familiar cases. Read the actual licence before you build on one of these — the condition is usually easy to meet and occasionally fatal, and which it is depends on your product rather than on the model.