I’m not really sure I understand the question.
But I’ll try. Many power supplies output different fixed voltages so there will be different types of internal transformers for each output.
And different power supplies also have circuitry that requires different voltages. This could be 12V, 5V, 3.3V or 1.8V etc.
And just to discombobulate, there are inductors and chokes that look like transformers. So you might be including these?.
But I’m just guessing that that’s your question.
Martin