Where do I find good IV curves?
You may not be able to find data on that part, though if you do need to use it in an &quot;unusual&quot; mode you might search for a part that is specified for that service.
For example, here is a datasheet for a similar device.
The only specifications given are that the current is guaranteed to be 80mA or less at 3.0V, recommended operating range is 2.5 to 3.5V and it is guaranteed to start as low as 2.3V (but only if you step the voltage to the motor, you're not allowed to sneak up on the voltage). That has probably been adequate information for them to sell millions of the devices at very reasonable prices.
If you are willing to pay a &quot;bit&quot; more Precision Microdrives offers a similar sized product with these typical performance characteristics:

It is anyone's guess whether those curves bear any similarity to the Amazon product or the Seeed product. There are also no guarantees, but it should give some rough idea of how it behaves.