I'll add:
Diphenoxylate (Schedule V anti-diarrheal) - Relatively inactive due to its low soluability in the digestive system, large doses "can cause codeine like effect"
Cyprodime = N-Cyclopropylmethyl-4,14-dimethoxymorphinan-6-one - Worlds most potent antagonist
Cyprenorphine - Buprenorphine with an N-cyclopropylmethyl group, its scheduled in several countries...
Pholcodine
http://opioids.com/pholcodine/ - Sold in cough syrups in some countries
And the peptides:
Endomorphin 1,2,3 - Endogeneous morphine!
Beta-Endorphin
Enkephalins - These are the natural pain killing opiods which exist in the brain, they are associated with the Delta opiod receptor (thus low euphoria) and can be increased by injuring yourself (not recommended) or eating DL-phenylalanine
DAMGO - Synthetic peptide which strongly antagonizes the Delta receptor, noted for its ability to prevent tolerance when administered with morphine
http://opioids.com/damgo/
http://opioids.com/tolerance/damgo.html
Damgo does a buncha other cool stuff too
A cool factoid about the endorphins is that they are not scheduled, and are recreational, however they're rediculously hard to synthesize, and extremely expensive for 10mg from Sigma Aldrich (not a source cause noone here could buy anything from them - no, dont even try, its like calling the DEA and asking them to sell you some weed). The problem with endorphins is that the body has enzymes which regulate them by breaking them down if there are too many, so the high would last 10 seconds, much like the post-coital glow. The other problem is that they would need to be injected intra-cerebrally (spinal may work!)
Good catch Piglet! Did you used to be a hiver? If so I ran across an old thread of you discussing N-(2-phenyl)ethyl-codeine
So Blah Blah Blah, I hope you have time to front post a beautiful compilation of every opiate known to man (sans minor variations on a theme, and non-active ones).