There are so many different functions transformers perform, so many manufacturers with their own standards, and so many different sizes in each category that something like what you want seems highly unlikely.
For example, what numbering conventions might I find on a transformer that goes to:
1. An entertainment system amplifier
2. An automotive battery charger
3. A microwave oven (high voltage)
4. A small appliance
5. Any other household items with transformers
In all the years I have worked with transformers, I have never heard of or seen a convention. Every manufacturer uses his own codes for his own products, that is, if he actually bothers. Quite often there are no codes except a company stock code, typically for microwves etc.
since there is a topic on transformers, can I ask is there any type of isolation transformers that would accept a 50mVp-p sine wave at the primary side? also, the primary side impedence would have to be more than 8ohm.