Pairs of entangled qubits (or Bell pairs, or EPR pairs) are a fundamental resource for quantum computing, in the sense that any computational platform that cannot generate entanglement will also be unable to provide a computational advantage. In two recent questions, Decoherence of spin-entangled triplet-pair states in the solid state: local vs delocalized vibrations and Entanglement transfer of spin-entangled triplet-pair states between flying qubits and stationary qubits, I asked about a physical scenario with the goal of generating entangled qubits pairs in the solid state. I know of this result of 2013, Heralded entanglement between solid-state qubits separated by 3 meters, which used photons and NV-centers in diamond, so this can be achieved in practice. Hoewever, I am not up-to-date on what is currently the best option.
My question is: What is the current technological status for the generation of entangled qubit pairs in the solid state? In particular, which options are currently fastest and/or most reliable?
 Thanks to Niel de Beaudrap who pointed that out in a comment.