Visible Name Tag on Invisible Mobs Minecraft

Invisible:1 only works for armor stands. For other mobs, you will need to given them the invisibility potion effect:

ActiveEffects:[{Id:14,Amplifier:0,Duration:2147483647,ShowParticles:0b}]

The invisibility effect, however, seems to hide name tags. To get around this, you could use an entity that is already invisible (area effect cloud) riding the main entity, and put the name on that instead:

Passengers:[{id:area_effect_cloud,CustomName:"Aria",CustomNameVisible:1,Duration:2147483647}]

The full command would look something like:

1.11+

/summon pig ~ ~1 ~ {ActiveEffects:[{Id:14,Amplifier:0,Duration:2147483647,ShowParticles:0b}],Passengers:[{id:area_effect_cloud,CustomName:"Oink",CustomNameVisible:1,Duration:2147483647}]}

1.10-

/summon Pig ~ ~1 ~ {ActiveEffects:[{Id:14,Amplifier:0,Duration:2147483647,ShowParticles:0b}],Passengers:[{id:AreaEffectCloud,CustomName:"Oink",CustomNameVisible:1,Duration:2147483647}]}

If the entity type doesn't matter (e.g: you only want to create invisible floating text), then you can use an area effect cloud or armor stand on its own:

Armor stand:

/summon ArmorStand ~ ~ ~ {Marker:1b,Invisible:1b,CustomName:"Stanley",CustomNameVisible:1b}

Area effect cloud:

/summon AreaEffectCloud ~ ~ ~ {Duration:2147483647,CustomName:"Aria",CustomNameVisible:1b}

(Switch ArmorStand/AreaEffectCloud with armor_stand/area_effect_cloud if you're using 1.11+.)