How many mods can you have in cracked minecraft?

You can put as much mods as you want in a cracked and regular minecraft.
There's no limit to how much you can put in but a limit to how it will work:

-Make sure the mods are compatible with anothers (some will say it won't work with another mod). If you Minecraft still crashes. Try doing a test by adding in one mod at a time and opening minecraft to see which mod doesn't work.

-Check if the mods work for cracked version. I'm guessing most should work but Cracked only lets you play single player, so no multiplayer related mods (if mods works in both single player and multiplayer, that's fine.

You should be fine and keep adding in mods, the more the merrier (until at some point it crashes).