I don't use the yellow and purple because the yellow is imperceptible against the light background and the purple is too easily confused with the orange and red. So I do the following:

Black - franchise cornerstone prospect. handle with extreme care.
Blue - blue-chip prospect. starter floor, all-star ceiling. make sure they have a clear path.
Green - legit prospect. more likely than not to be a contributor. make sure they get playing time.
Orange - high-risk prospect. may be a contributor with enough good breaks. keep an eye on them.
Red - one or two intriguing qualities. likely tops out as useful minors depth. don't let them stagnate in the low minors but don't expect them any ML contributions.

I've contemplated folding the black and blue dots together and using the black dot for something else since it gets used so rarely--I like the idea of using it to ID bad DITR candidates since it is always annoying to check 50 individual profiles.

I use most of them, just with possible/borderline future MLB players. Red for unlikely all the way to Purple or Blue for likely with more upside.

I really like the DITR markings to ensure I deactivate the right guys. I'm going to have to implement that going forward. I try to keep it simple so that I can manage my team from my phone if needed.
Green: ML-caliber
Yellow: keep an eye on them, could be a fringe ML if lucky
Blue: respectable MiLB player
Orange: pure innings eaters in LoA / RK
Purple: keeping them for the memes (e.g., draftee who graduated from a penitentiary or my real-life college, or have a funny name like "Charlie Unknown")

ha, love the purple for the memes.

Blue = Is or should be a ML talent

Green = Is or should be a AAA talent

Yellow = Is or should be a AA talent

Orange = Is or should be a HA talent

Red = Is or should be a LA talent

Fuscia = won’t leave Rookie Ball unless needed to fill out a roster or as an injury sub.

The biggest use for this system so far is to easily and quickly identify players I need to protect in the Rule V. Also helps to simplify my assignments and promotions.

Blue = one of the rarest colors of diamonds, so DITR.
Green = top prospects
Yellow = middling prospects
Red = Any 34+ yr-old vet on my 40 man roster.
Purple = Rule 5 draftees

Green. Will be a major league starter.
yellow - possible ML starter, likely contributer
red - may have a **** at ML in some way.

I don’t use the rest. Every player gets a color (or no color, which means will never make the majors) when they are added to the roster.

I update DITR, and downgrade reds once they are 27 if they haven’t made the majors.

Green is my top tier prospects think ML starter to HOF
Yellow is my second tier prospects backup players/ relievers / starters on weak teams etc...
Red are bust players that are just their for minor league depth

Blue denotes Diamond In the Rough players
Purple is for players that I have drafted or acquired specifically for their potential to be good if they get hit with the Diamond In the rough
Orange is for the players that I have acquired or drafted specifically to be AAAA players or have AAAA potential. Think high stamina pitchers, high durability pitchers with 40 splits or decent fielding players.

My coding...

Green is for Minor Leaguers that absolutely must be promoted at seasons end and are on their way to big leagues in their future OR can be called up in an emergency

Yellow is for minors that may or may not make the bigs. Must promote regardless and protect in rule 5

Pink is for any player I sign in FA. Simply a curiosity of my team make up and how they came to me

Blue is for any player I acquired via trade. Again to remind myself of how I aquired them when looking at team make-up

Red is for career Minor Leaguers. They have a skill set that is valuable, but only in minors. For example.. pitcher with ok splits but weak pitches or a positional player that is mediocre across the board. Doesn't entirely suck, and worth keeping in the system to win games in the minors

Uncoded is only for minors. They are with the franchise this season and beyond that I don't care much

My current team is 99% FA and trades with one homegrown All-Star. Just interesting insight for me personally