In a 3d printed game board tiles that I'm designing, there are game pieces that will be placed down by players on specified locations. I'd like to have these pieces light up with LEDs. I've bought a bunch of pogo pins from amazon and the plan is to use those to pass the DC voltage from the game tile to LEDs in the pieces. Every player will have different color pieces and the LEDs' color to match the player's color. Along with these player pieces, I'd like to add additional LEDs to the game board tiles for aesthetic purposes. At the present I'm looking to use Chanzon 0603 SMD and Chanzon 1206 SMD LEDs.
In my research, I understand that they have a forward voltage that must be met to turn on, and sending too much voltage can kill them. I also know that the LED's need to be current limited with a resistor or else they'll burn out. Since I'm looking to power the LEDs with batteries, the supply voltage will drop over time as the batteries die and I should be using a constant current led driver with will accept a higher voltage and current limit the supplied power to be what the LEDs are needing.
I've found lots of examples on how to make a constant current LED driver using things like mosfets and n/p transistors. However, in all the examples I've come across they all have something in common; the amount of LEDs being driven by the example circuit are fixed which means that the calculated resistor value only works for the given required milliamps of the LEDS being used. Also, most of them usually say to not mix types/colors of LEDs due to the different forward voltages and current requirements. These examples don't help much as with my intended usage, the amount and colors of LEDs will change based on what game pieces are placed on the playfield.
What would be required for a circuit that's designed to power/drive an unknown amount of LEDs of differing types and colors from a battery voltage source that will drop over time?
I'm looking for some general knowledge targeted at my use-case as well as pointing me in the right direction so that I can learn how to design the circuits myself. It's very possible that I'm lacking a basic or key understanding of electrical components which has caused me to go down the wrong path in my journey of self education.