Role-Playing Elements as Player Character Cards

Don't you just hate it if you can't keep track of your Character's motives, limitations, nuances, biases, etc...

Can I try to fix that?  

You've heard of Death by Modifiers, the design rational that limited use of modifiers in DnD5E, lets prevent "Death by RP-Elements." Lets just have a few, 2-5, such Role-Playing Elements that will influence the PC and the Player will try to pursue in the course of game session.

I'll put these notes in some Index Cards. So that I can physically track it and anchor it to my attention after repeated play sessions. Let's call them Player Character Cards (PCC for short).

Player Character Cards

PCCs are Cards, they can be index cards where only the Player knows what's behind the card. It can have Motives, Behaviours, Biases, Missions, Secrets, or any Complication that will give the PC a stake or Influences the PC's course of action or decisions.

If a Player is pursuing a course of action or mission, then he will want to remember his motives and limitations. For every "Card" he can relate to the Objectives of the Course of Action then the more character development he can earn.

The GM asks if he can look at the PCCs and takes notes if the Player is pursuing it, and works with the material the Player gives him. The more a PCC is used, the more the idea gets developed.

In these Cards I'll put the Following:

• The Role-Playing Element: Stuff that gets me to RP, influences my character's decisions, and complicates the adventure. Stuff I want to GM to know, and throw at us. 
• My Character's name and rationale. (so it does not get lost). 
• Some Red-Herring Cards. Maybe Wishlist Challenges or Notes for the GM. 
• ex. Can we fight goblins today? Can we go to town? I want to check out the old Ruins etc... 
• In the back of the Index Card as another Red Herring: any identifying mark, red herrings, things that will psyche the other players lolz. 
• "I want to dig into the Clerics's shady past?" player to GM note. 
• There is a Limit of up to 1 Open Secret, if the Player decides to limit his secrets. As part of the fun he has to Hide stuff from the other Players (consider it a Fog  of War or Information Asymmetry; stuff that cannot be known for certain or would be very difficult and complicated to communicate). 
• What's important that no one, but the GM sees these notes. He just facilitates, it doesn't mean he will do everything in them. 
• GM will keep the player off-balanced and will tend to facilitate a pretty challenge scenario with a very good risk of failure and set back to keep things challenging.
• Write Legibly! 
• Make sure you can Spin this RP-Element in a way that is fun. Make suggestions to the GM! ASK: "How can my PCC/RP-Element move the plot or make the game or story more interesting for the others?"

What the GM does with the PCCs

• Check if the PCC is being RPed. Facilitate, Encourage, and Enable the Player to RP the PCC, especially if it is a Hindrance and a Complication. 
• He keeps notes, but the Players Volunteer and Remind him of their PCCs. 
• Reward them for helping you make the Game more fun for (you the GM and) for everyone else. 
• Maintain the Secrecy that makes it a fun Guessing and Meta-Game as everyone else tries to figure out each other's motives. 
• Set a Difficulty and Reward by how much of these PCC/RP-Elements should be pursued in the course of play. 
• CONSISTENCY. As the RP-Element Developed, then the GM and that Player needs to maintain consistency. 

GURPS

• No point Value for Disadvantages. Particularly those that meet the criteria for PCC. (I use Trait Tables to Roll Up these elements)
• Give the Players more freedom to rewrite or develop the intensity of the PCC or RP-Element.