Tiny black holes left over from the Big Bang may be prime dark matter suspects 

 Don't rule out primordial black holes as dark matter suspects just yet! Particle-sized black holes may resist evaporation, surviving long enough to account for the universe's most mysterious stuff. 

https://cdn.mos.cms.futurecdn.net/XsaWoUNwD2os4gADQgB6gd.png

https://www.space.com/tiny-black-holes-big-bang-prime-dark-matter-suspects