© 2020 World Scientific Publishing Company. We review the status as regards to the existence of three- and four-body bound states made of neutrons and Λ hyperons. For interesting cases, the coupling to neutral baryonic systems made of charged particles of different strangeness has been addressed. There are strong arguments showing that the ΛΛnn system has no bound states. ΛΛnn strong stable states are not favored by our current knowledge of the strangeness - 1 and - 2 baryon-baryon interactions. However, a possible Ξ-t quasibound state decaying to ΛΛnn might exist in nature. Similarly, there is a broad agreement about the nonexistence of ΛΛn bound states. However, the coupling to ΞNN states opens the door to a resonance above the ΛΛn threshold.