A good topic, in the current market. No new, quality RAT or botnet has appeared for a while. Every single RAT is just a copy of CraxsRat. CraxsRat itself is a mess, with many bugs across its variants.
As for botnets, we have only two good options: Hook Botnet and Octo Botnet.
Some other options have appeared, but they seem to be just copies of these two botnets' source codes.