Hey! Thanks for Viewing!
In this Blog I will be showing you how to spawn mobs with custom nametags that stay up permanently and other cool features!

#1 FallingSand
Get A Command Block and type inside the following:
"/Summon FallingSand ~ ~1 ~ {TileID:#YOUR BLOCK ID HERE#,Time:1}
That Command will summon falling sand to spawn one block above the command block and place its self as whatever block ID you put in! Also just change the ~'s To whatever co-ordinates you'd like it to spawn at!

#2 Name tags for mobs (That stay up!)
This could originally be done through NBTEditing programs, but now its a command!
Type this into a command block:
"/Summon #MOB HERE# ~ ~1 ~ {CustomName:"CustomNameHere",CustomNameVisible:1}
That creates a mob with a nametag like a player!

#3 Mobs riding mobs!
You can stack entities on top of each other! With this command:
"/Summon #Lowest Mob Here# ~ ~1 ~ {Riding:{id:#Mob#}}"
This can also be stacked! Like So (Here's some stacked giants):
"/summon Giant ~ ~1 ~ {Riding:{id:Giant,Riding:{id:Giant,Riding:{id:Giant,Riding:{id:Giant}}}}}"

#4 Some basic syntax so you can guess other features!

To Add One basic tag to the Mob use:
"/Summon {TagHere:TagValueHere}"
And for tags that use strings:
"/Summon {TagHere:"String String String""

Here's an example of a non-string tag:
(Command Block)
"/Summon Pig ~ ~1 ~ {Invulnerable:1}"
WARNING: Be careful with this! You can't kill it.
NOTE: In NBT Boolean values are 0 = False 1 = True

Thanks for reading, i'll be adding more features as soon as I find them!