Two "dark matter" candidates that illustrate physicists' quirky sense of humor: WIMPs and MACHOs
“WIMPs” are Weakly Interacting Massive Particles (neutrinos have only a tiny mass, but there are SO many of them that they are a candidate)
“MACHOs” are Massive And Compact Halo Objects (dark objects — rogue planets, burned-out stars, etc. — in galactic halos, above and below galactic disks)
There are other candidates, of course, but these are the two I know of with the silliest names.