So, I've been on and off of this game for quite sometime.  I see some of the organized crimes that exist.  But, I think loan sharking would be a nice racket for everyone to take part in - similar from drugs.  It's actually more common in organized crime than drugs.

How does it work?

Much like the drug racket here, you could loan out $10,000 (just for an example) to an NPC or what have you.  You can determine the interest rate that this loan is dealt out (1-10%).  So if you loaned out the 10k at 5% (or 5 points), in real life it would be a collection of $500 a  week.  This could be a daily collection instead considering money moves faster in the game.  There could be instances where you have to be forceful to collect the money etc.  

Even within the same crew, a crew leader could loan X amount to their own crew members at 1% and the crew member could loan it at 5%.  The crew leader is repaid their 1% and the crew member keeps the difference to build their loan business up.

Even with robberies - armed robberies of convenience stores, bars vs. banks.  Some could have a higher pay out, but if you have a higher target, the feds could be on you quicker which would result in higher prison time.

These are just basic things

+1 I like this idea. 

It could be worked like the CAs are. You buy one with a set percentage say 5-15%, and “loan” them the cash, up to a limit of course. Just like with your CA selling drugs, every 24 hours you can call it in to have the loan repaid. 

Another factor, we have cities where people travel.  Bosses can certainly designate taxes as they are now.  However, we can also simulate other independent groups showing up here and there in various territories.  It is then up to each designated family/gang to extort these independent drug dealers/bookies/loan sharks/burglars etc.  In doing so, that allows for the businesses to exert more influence.

Additionally, certain businesses of different types - local businesses, construction companies could be set in territories for families to extort for protection.

+1 for me on the extortion business idea. Could be set up like the OCs but only for family members. Say run by a Boss or higher. Could just add another element of making money for the family. 

I like this idea. In addition to loan sharking and robberies, maybe a ransom? Hold an NPC for 3-6 days and you get paid say $350-1000 a day. Once that time is up if no one pays that NPC dies and another is randomly generated. If they do pay then that npc is released. 

Even the truck rob business