Duel Links Farming Strategy Discussion

Farming in Duel Links involves achieving high point scores (up to 8000) against legendary or standard duelists to get the maximum amount of prizes, which is necessary to have access to competitive cards and currency for the Card Trader. Some strategies will need to be supplemented by Shiny or Prismatic cards, which always offer extra points, even if those cards do not further the strategy.

So the aim of this thread is the discuss your farming methods with each other and find optimal ways to farm.

I personally don't farm SD. I only farm LD. 

But you  can find auto-decks to farm Stardar Duelist, although there's no much to farm.

Man look at all of you able to farm because you got good cards while I can't because I really do not spend money on it.

I have terrible cards just have friends who are God's at DL

I have spent exactly 0 $ on this game and for climbing the ladder and doing well in events you get to pick a card of your choice. That's how I got cards that never dropped for me cause my luck fml. To get over 8 k points there are several key cards that you need :
1) gravekeeper's vassal (reward from Ishizu) + Union attack and spell reclamation (union attack is a super rare reward from Yugi when he shows up in the world with his magnet deck) + secret pass to the treasures( a common card )
2) piranha army + a big monster (4200 atk + so ultimate blue eyes, master of oz , buster blader with dragons in grave etc) + secret pass to the treasures + gift of the martyr (common in chaotic compliance set)
3) a magical beast cerberus (from card trader) deck that has only it as a monster and 19 spells that can be played and include some way to pierce through def (big bang shot) or to change def position monsters to atk ( enemy controller or block defense ).