Meng mirrors
The Meng mirror (named after its inventor) is essentially a perfect mirror - based on horrible, horrible metric manipulations - for photons and other bosons. At least until its capacity is exceeded and it undergoes catastrophic collapse; or what in modern systems, which prefer to project their mirrors as interlocked “scales”, is called a “burn-through”.
They have no effect at all on other particle classes apart from minor interference with boson interactions in the course of passage; i.e., kinetics sail right through 'em.
Originally invented both for shielding torch drives, and because gamma-ray mirrors are very, very useful in improving drive efficiency.
Antithetikon emitters
Not antimatter (these are strict ray shields, and don’t affect fermions), but they are anti-energy, in a sense; the notion is to project a wavicle such that the the attack and defense interfere and sum to zero everywhere where it matters (and hopefully only positively interfere in places where it won’t).
This was never a terribly practical technology (needs FTL sensors to work well without letting yourself be hit in the first place before reacting to it, outside purely experimental rigs; requires bizarre ship designs to fit around interference patterns; effectively turns shields into anti-weapons with many of the restrictions of weapons; etc., etc.) in the first place and while it was developed to the point of functionality, it never really made it out of the experimental classes, except in the subfield of gravity shielding (see “get your equal and opposite gravity”). Even there, it’s terrible, and survives primarily because there is literally no other option.
Probability unseller
@doctorcatfish nails this one.
(P.S. HICAP isn’t an armor compound, strictly speaking - it’s the waxy neutron absorber that’s mostly used for shielding reactors and torch drives so they don’t fry the squishies. But a good thick layer of it crammed into your armor just in case the oppo are using particle-beam weapons doesn’t hurt anything, especially since its physical characteristics let you cram it in between layers of Whipple shielding.)