I second that ^^^^^^^^, but would add that almost any "RepRap" stepper stick in that form factor should work.
Here are just a few (hundred) links for them on FleaBay.
Other than having to set the drive current (like the originals) they should be plug-and-play replacements.
Or, you can upgrade to DRV8825-based boards as @Tin_Falcon mentioned, which will do finer microstepping (1/32 rather than 1/16).
And of course there are TMCXXXX-based "quiet" drivers such as these-
But I must confess that I had no luck using the TMC-series drivers myself, and they are set up differently than most RepRap drivers jumper-wise.
They did weird things on my printer so in the end I gave up on them.
I would not recommend these for the extruder drive, only for the XYZ motions if you want to use them.
My present board is a 32 bit MKS/SmoothieWare setup which is DRV8825-based for the stepper drives.
I am quite happy with it, and am running 1/32 microstepping on all motors.
So yes, you have many options when a stock stepper driver stick goes bad.
That is one of the beauties of the modular controller design that was used for the R1's.