All of these strats are applicable to all categories unless otherwise noted.
Optimal Card Selling: After opening cards, they are added to your inventory where they can be sold. When you are ready to sell your cards, instead of clicking the "Sell All" button, sell the cards individually. Doing this will give you more money for each card rather than getting a smaller amount of money when selling all. For speedruns, I tend just to sell the rare cards (the cards on the right) and click sell all to sell the rest of the cards. The reason you get more money selling individually than by selling all is because when you click "Sell All" each card is reduced to 30% of it's worth. So by selling the cards individually, you make over 3x what you would by selling all.
Avocado Technique: When you have amassed $300, it's optimal to go straight to the "Mayan2012" upgrade rather than the other upgrades before it. Mayan2012 gives a chance for avocados to spawn which, when clicked, gives you $300, returning your investment very quickly. You can exploit avocado spawns by rapidly clicking between the "Inventory" and "Back" buttons, as avocados can only spawn when a new window is brought up. Alternatives to inventory include the trophy screen, the casino screen, and closing and reopening the game (however this one, in particular, is very slow).
Trophy Room Avocado Spawning (100% exclusive): As mentioned above, the trophy room can also be used to spawn avocados. This is only applicable in 100%, as getting the trophy room would already complete your run for any%. The reason this is helpful relies on two things. 1) The fact that the "Trophy" button is closer to the back button than the inventory button is. And 2) The fact that avocados only spawn in the middle third of the screen and can spawn off the top of the screen. I don't have anything to confirm this observation, but I think that avocados always spawn when closing a window, but they have the chance spawn off the top of the screen. This could explain why avocados can be seen half off the top and why sometimes the chance to get avocados varies. Using the "Trophy" button puts your mouse closer to the top of the screen, more likely to be closer to an avocado, should one spawn. While this may not seem like a lot of time saved, it adds up over the course of a whole run. Another thing to note is that, while technically it is possible in the Lucid category, the amount of money you lose purchasing the trophy room upgrade probably outweighs the time save by using the button.
Cost of Cards: While not technically a strat in and of itself, there is something that should be remembered. Starting from the first card, the value of each following card is doubled. The white cards are $1 when sold, so that means that the red cards are $16, the green cards are $32, the cyan cards are $64, and the pink cards are a whopping $128. This is just something to keep in mind when going for quick any% runs.
That's all the strats I can think of off the top of my head. If there are any more, just say and I can add them.
