Easy but little complicated unlimited crystals (with enough clicking).
Obtainable trough Epic Achievements.

Instructions:

look how many stickers did you peel. 4byte*1
Peal a sticker.
Look again to be sure.
Now loook at what level of mision you are for pealing stickers (1 - 5). Look for it 4byte *1. I found 3 adresses.
Gain levels in mission trough changing ammount of stickers pealed.

If found number of mision level freeze all 3 adresses at 4 and click fast Claim, or freeze at 2 and use autoclicker 1ms.

Now u get crystalls every time you click claim. Got 25k and dont know what to do with them. Game got borring.