Laser enrichment is an emerging technology that promises to make isotope separation significantly easier than it currently is;  (naturally, this has all sorts of fun concerns for proliferation) However, one possible usage could be separation of exotic fissile materials. Looking at this chart; Some useful nuclei (such as Am-242) have other less useful isotopes (for instance Am-241 and Am-243). Another example which comes to mind is Neptunium-236; per wiki it has a critical mass of about 7 kilograms, and a long enough (154,000 years) half life that it shouldn't be too obscenely difficult to handle. However, it is commonly found with Neptunium-237, which is somewhat less useful (having a significantly higher critical mass, and no significant advantages over Uranium-235), and is difficult to separate, due to the low difference in mass between 236 and 237. Use of laser enrichment could allow sufficient production of Neptunium-236 to allow it to be used in niche reactors (I believe @Collimatrix once proposed using such isotopes to power NTRs), or to make a quite small atomic weapon. (Neptunium-236 is also a decay product of Plutonium-240, the worst Plutonium, though I don't know if that's a viable production method. Nobody tries to make Plutonium-240 anyway.) An alternative use for laser enrichment could be to separate out particularly annoying transuranic isotopes from nuclear waste. Possibly, these could be blended with other, more common isotopes and used as fuel, for various research applications, or even just burned up.