It's been clear through the last few weeks that even though TCO isn't going anywhere it's not very stable. Not only that but it's a very iffy way of playing as you can break all the rules without ever noticing it. Here I present to you this new engine: the modded YGOPro2! Here's a little showcase by the lovely Szefo09: https://www.youtube.com/watch?v=95cakv08RQw
For now this is just one-man project. Any coding help would be very appreciated. The engine is written in c++/c# and the mod is in c++. Even if you can't do any coding I still encourage you to test it out and report any bugs/ruling errors. The creator seems very passionate about it as he does fixing almost instantly. Here's the github page: https://github.com/Hello23-Ygopro/ygopro-dm
I recommend using Szefo09 server for playing as he keeps it up to date and runs it full-time. Currently cards from DM01-DM12 are coded in and DM13 is on its way. The engine has limitations, to go around them the tapped mana is placed in graveyard for the turn (the cards are still separated by effects, just not visually) and you can't have more than 5 shields nor 5 creature in the battle zone. To solve those issues we would need to edit the engine's code (which is open-source as well) but it's difficult.