When doing ''/clear @a #minecraft:'' it has a list of catagories, but there's a few block catagories missing (presumably oversights when updating and adding new blocks) 

the missing catagories are: #minecraft:concrete (all concrete and powder concrete forms), #minecraft:convertable (concrete powder) 

specifically need to clear concrete items for a minigame im making, and i rather not have 16 command blocks with 1 for each type of concrete