Idle master setting is default on idle games wiht more hours than 2 invidually and then games under 2 hours simultaniously. This is due to trading cards normaly start dropping whne you're past the 2 hour mask.

Just let it do the job and you will get card drops, so long you are in-game you can get drops. Past 2 hour mask idle master idle 1 and 1 game until no more card is left to idle

引用自 K. Wrecks：

It may not be Idle Master causing the issue. I've been playing a game I just bought for 1.5 hours and have 5 drops available but haven't gotten a single drop.

Games you buy on Steam need to be played for 2 hours before they start dropping trading cards.

All the cheap games