Idle Master will do up to 30 games if you have that many with less than 2 hours of playtime. You can also manually start a bunch, but you may run into problems depending your computer's specs and whether the games have a launcher window or load up the full game.

Once you have received all your free drops, you have 3 options to complete the badge.
1) Purchase the cards off the Market.
2) Trade with other accounts
3) Wait patiently for a booster pack

There is no method to reset your free drops. Crafting a badge will not give you more drops. Selling your cards will not give you more drops.

Have you read the FAQ?
http://psteamcommunity.yuanyoumao.com/tradingcards/faq/

Non-Free-to-Play games give half (rounded up) the total number of cards in the games set. Duplicates count against your allotted number of free cards. Trading/Selling/Using your free cards will not give you additional/replacement cards.

http://psteamcommunity.yuanyoumao.com/tradingcards/faq/

Due to changes in the refund policy, you now need 2 hours of playtime before normal card drops start. Most games take ~30 minutes per card but can take up to 1 hour, that means your first card will occur ~2.5 hours of playtime, but can be up to 3 hours.

Could just add a shortcut into the Startup folder
https://support.microsoft.com/en-us/kb/2806079

I would assume annoyances of making sure Steam started before Idle Master and how often it'll be run once you catch up on your backlog of games outways the possible convenience.

Double check your Badges page that all 15 have drops remaining. Free-to-Play games do not give you free drops just for adding them to your library, you must spend 9$US for each drop. Non-F2P games only give half (rounded up) of the number of cards in the set. Duplicates will count against this number. Trading/Selling/Using these card will not give you additional/replacement drops.

Due to changes in the refund policy, you now need 2 hours of playtime before the normal card drop system starts. Idle Master prioritizes getting all games with remaining drops up to the 2 hour mark. If you have 5 games with less than 2 hours of playtime, that's why you only have 5 games that start idling.

Once all of your games have 2 hours of playtime Idle Master will switch to idling 1 game at a time since running multiple games simultaneously at best is the same as running them sequentially. There have been reports that multiple games will completely prevent card drops, but no official word on such a change.

Początkowo opublikowane przez Seiferu:

The keys are like CS:GO pretty much just skins is what you get from the keys and crates.

And apparently purchased for 1$. 9 of them and you'll get a card. What comes in the crates is irrelevant for trading card drops.

Początkowo opublikowane przez Seiferu:

On unturned you can only buy a gold account,which costs like 5 dollars,But some people who dont have gold do actully get cards

I don't play Unturned so I might be missing something, but a quick look shows you can purchase keys for 1$US, I'm not motivated enough to dig deeper to see if there's more items for sale.

Are they getting cards through playing the game, or acquiring cards through other means? You can purchase/trade for the cards without earning any drops.

How much have you spent on those games? F2P games do not give cards just for adding them to your library, you must spend 9$US for each drop. If you have drops for those games, then have you tried adding the undesired games to the blacklist so Idle Master will not attempt to idle them?