I had this idea just now for fragments for flawless materials. Getting 4 fragments allows you to craft flawless items based on the fragments. 4 flawless diamond shards make a flawless diamond, 4 flawless gold nuggets makes a flawless gold ingot, 4 flawless lapis powder makes a flawless lapis, etc. These fragments would be dropped on occasion by legendary and heroic mobs, being more common from legendary mobs (Thinking maybe 20-50%) and very uncommon from heroic mobs (Thinking maybe 5-10%)
Ideas for Items for each nugget/fragment
-Flawless Diamond Shard is custom enchanted prismarine shards
-Flawless Iron/gold nuggets are custom enchanted iron/gold nuggets
-Flawless Lapis/Redstone/Glowstone powder is custom enchanted blue/red/yellow dye
-Sturdy Wood Chip is a custom enchanted wood button
-Perfect Leather Scraps are custom enchanted rabbit hide
Ideas for Items for each nugget/fragment
-Flawless Diamond Shard is custom enchanted prismarine shards
-Flawless Iron/gold nuggets are custom enchanted iron/gold nuggets
-Flawless Lapis/Redstone/Glowstone powder is custom enchanted blue/red/yellow dye
-Sturdy Wood Chip is a custom enchanted wood button
-Perfect Leather Scraps are custom enchanted rabbit hide