We have discussed in other threads ammunition with color markings on the casehead. I recently ran across an interesting company
105C Vine St
Monroe, GA 30655
Their nitch is that you send them your pistol and they will work out a custom load which gives the best performance for your pistol.
If you don’t want a completely custom load, you can order one or more of their “Sample” packs and try out a number of their loads. I recently ordered their 9x19mm Sample pack 12. As you can see the cartridges have the color lines on the headstamp. I’m sure they are not the only outfit that does this and as mentioned, some reloaders use this to identify their brass or the number of times they have loaded the case. Still this just proves that there is no end to cartridge variations.