I found a box of stepper motors:
85x85x66mm 1.8 degree 2.4v 4.5a
56x56x75mm ?? (with driver)
42x42x40mm 1.8 degree 2.8v 2.0A (with encoder / driver)
42x42x23mm 1.8 degree 2.0v 2.0A (with encoder / driver)
The bottom three have some electronics in them, some of the components are:
IRFB4332PbF 42A FET x2
80mΩ current sense resistors x2,
8-Bit Parallel DAC,
ATtiny13 mpu (atmel 0514D),
something that looks like a memory chip (s29al008070tf102) ,
large 270uH inductor plus a couple 47uF caps for LC filter.
If I can't figure out the DB9 connector signals, I could just bypass the electronics and use external driver if needed (but lower 1.8 degree steps).
On Ali I seen this this low cost one (only 32 micro steps)