I do not know how many people who read this know a lot about command blocks, but I have been scouring the internet for the answer to my problem, and it appears the solution is not even in minecraft. This is a rather small, and possible unnoticed thing about command blocks, let me give you and idea of what I am talking about.

I want to have a /summon command and have it summon a evocation fangs under all entities in the area besides Players and Items.
I can easily do
/execute @e[tag=(mytaggoeshere)] ~ ~ ~ execute @e[type=!Player,r=5] ~ ~ ~ /summon evocation_fangs
But this makes the fang spawn underneath items, too.
I can do
/execute @e[tag=(mytaggoeshere)] ~ ~ ~ execute @e[type=!Item,r=5] ~ ~ ~ /summon evocation_fangs
But this makes the fang spawn underneath players.
I have tried to do
/execute @e[tag=(mytaggoeshere)] ~ ~ ~ execute @e[type=!Player,type=!Item,r=5] ~ ~ ~ /summon evocation_fangs
But it only regards the last one, and summons fangs under the player.
I could have two command blocks, both doing the same thing but switching out !Player for !Item, but they would cancel each other out and fangs would be summoned beneath both items and players, along with all other entities in the area.

I propose that Mojang add an "And" or "Or" selector specification, so that one would be able to make this work and have it look like.
/execute @e[tag=(mytaggoeshere)] ~ ~ ~ execute @e[type=!{Player,Item},r=5] ~ ~ ~ /summon evocation_fangs
or something. That would cause it to work and for fangs to be summoned under all entities in the area except players and items.

This is just one example of how the "and" selector specification could help command blocks function in a wider spectrum.