Quant deserves more attention in this forum:

A new article just came out, this time from Altcoinbuzz:
https://www.altcoinbuzz.io/reviews/altcoin-projects/quant-overview-the-connectivity-backbone-for-blockchains/

It is - at the moment - the only crypto project that can connect all different networks (blockchains, other DLTs, legacy systems, offchain data from databases) without adding another Blockchain / consensus.
Its done through an extra layer (they call it overledger) that sits on top of the existing blockchains, and it uses a complex filtering and ordering mechanism.
Details and examples of such Mapps (multichain applications) can be found in the Altcoinbuzz article above, or you can check out the Quant medium articles  from Seq (he is the GOD of Quant): 
https://medium.com/@CryptoSeq