Microsoft Solitaire

Can be done with 50 games of spider.
Start a new game of spider and keep clicking the deal pack until all cards are on the board. ( That's 5 clicks)
Get around 50 cards per game.
Once all cards are dealt, click start new game.
Rinse and repeat. Take around 10 mins.

Alright, for those who want to get this achievement without losing a finger by pressing a button for 8 hours or more I would suggest you guys to use an Auto Clicker, there are many versions through the Internet, just search for it (I used GS Auto Clicker, pretty simple and functional)... I think some people from TA will consider it as some kind of ''Cheat'' but if you wanna grind it by yourself go ahead and keep pressing a button over the cards for 8+ hours ... I'll pray for your fingers don't rot

Now, choose whichever game mode you want that is possible to do it... I did it on Klondike game mode, just put your mouse over the stock cards and let the Auto Clicker do the ''magic''. It took me 2 hours and 30 minutes with GS Auto Clicker to unlock.

I'm not doing any advertising to a specific program, I'm just stating which one I used that worked perfectly.

Peace.

Best method imho is to do TriPeaks, you can easily get about 400 cards in about 5 minutes on the endless random 3 deal option (about 2 hours to hit the achievement with no breaks assuming you are 100% optimal which nobody is). Just spam click the deck till it's empty, click the deal button to reload the deck, repeat until game over, then click New Game and repeat.

If you have no ads (either from the subscription or a system-wide ad blocker), on some games it will give you an option for an extra boost, choose "Give me an Extra Deal" to add an extra round of spam clicking before having to reset the game. That will save a tiny bit of time by not having to reset as often but only if no ad loads so you should avoid it if you have ads.

The best way from what I can tell to get this is to open up a game of Spider Solitaire, click on the deck 1-5 times, and then click undo 1-5 times respective to however many decks you placed. Whether you do 1 or 5 I don't think the time difference will be changed. It takes the same amount of time to place five decks and click undo five times as it does to place one deck and undo it five times in a row. I did this for about 20 minutes and got from 48% done to 100%, so starting from scratch will probably take you about 45 minutes depending on how fast you click.

Possibly the easiest/fastest way to unlock this achievement:

1. Start a game of Spider Solitaire.
2. Click the card stockpile in the lower-right corner 5 times, this will deal(flip over) 50 cards.
3. Click the Undo tab 5 times(located under card stockpile).
4. Repeat steps 2-3.

This method takes approximately 30 minutes as it requires repeating steps 2-3 a total of 200 times(or less depending on how many cards you flipped previous to unlocking this achievement).