It takes so long for cards to drop nowadays..

Get alt, buy game, activate family sharing, play the game on alt, refund on main.

Shouldn't that work? (I know that you don't get drops if you play a shared game, but I mean that the refund system can be sidestepped)

Card drop rate is game specific, ranging from 15 mins to 1 hour per drop. Due to recent refund policy of Steam, you are eligible for getting drops after you have spent at least 2 hours in the game already. Using Idle Master may not be appropiate as it will take longer and often you will get the last drop after a long time (10.5 hours to get the 3 card drops of How to Survive)

Idling exists.