I would say that the dissociatives (i.e. NMDA antagonists) have the most risk for addictive use, that is if you consider them hallucinogenic/psychedelic. Unlike traditional hallucinogens, these drugs can be used on consecutive days, and still be affective. Also, the headspace is generally less threatening and more predictable than traditional psychedelics. The disconnection from emotional response can be all alluring, and these drugs can even produce a degree of euphoria in some people. There are also many examples available on the web involving addictive use of DXM, Ketamine and PCP.
Addiction to MDMA and other empathogenic stimulants is somewhat self limiting IME. While the extreme euphoria frequently experienced during MDMA trips can make people want to chase the high, the onset and degree of tolerance makes overly frequent use not very effective. Dosing these substances two days in a row leads to greatly diminished effects the second day, and euphoria is generally not present even while stimulant side effects are (and it takes far higher amounts the second day to achieve even that, taking the same dose again will be much weaker). The body needs time to replenish neurotransmitters before proper effects return, I would say at least a week is needed between rolls to feel a desirable high (even weekly dosing is too much IMO, and tolerance will be present).
I would say there is little chance of addiction with the traditional psyches (and delerients i guess), they're just not that kind of drug. I think escapism is a big part of addiction, and psychedelic trips are like the opposite of escapism, they make you examine yourself on a very deep level. Taking a psychedelic while in the addictive mindset would likely be very unpleasant.