Here is the full solution for CraftConnections Day 21. Each group is shown with its difficulty colour and a redundant shape, so it stays readable if you are colour blind.
Classic — Day 21
● Dyes White Dye · Black Dye · Gray Dye · Light Gray Dye
▲ Only found in the Nether Crimson Stem · Soul Sand · Glowstone · Warped Stem
◆ Crafted with string Scaffolding · Bow · Lead · Loom
★ An enderman can pick these up TNT · Red Sand · Gravel · Warped Nylium