One new model LMG900TMP was found in LG database and info from LG is shown below:

From its name, we are confident this model is for T-Mobile. As we can see in the screenshot, this model is manufactured on Jul. 7, 2020, hoping it will be available soon.
So far, LG VELVET has been released in European, Canadian, American, Australian, South American and Taiwan markets. You may check VELVET variants you are interested in via links below:
• LMG900EM for Australian market (LG)
• LMG900EMW for Taiwan market (LG)
• LMG900UM1 for ATT (ATT, LG)
• LMG900UM2 for Canadian market (LG)
• LMG900VMY for Verizon (Verizon, LG)
If you want to have a look at all VELVET variants you may check kdz.gresslg.tk.