The Minor Planet Center provides a list of recent MPECs. It can be a little difficult to find a particular older MPEC. Therefore, I've built an index starting at the first MPEC in 1993 and continuing to the present. Or use the grid below and select the year you're interested in.
My index also gives (for MPECs starting in 2017) a bit of data concerning the orbital elements, Earth MOID, and size of the object. That's because I'm sometimes trying to find "that object I saw a week or so ago that came really close to us", or "that TNO that got MPECed a while back." For older MPECs, you don't get the orbital elements data; I've not bothered (as yet) to re-run the program to generate indices that include an element summary.
Starting in 2018, the codes for the first four stations in the MPEC are listed, with the discoverer (if any) in bold.
Source code used to build this index is available. That repository, as its miscell name suggests, has "miscellaneous" programs in it; you'd be looking for mpecer.c and reverser.c.