Have*

Which edition?

5e.

Poo. I’m old.

I play but I'm not sure I'm the best person to ask try @kamatsu

I'm a DM for a 5e campaign. Watchu need?

Okay, so I'm a Pact Weapon Demon Warlock. I want to multiclass into Sorcerer(Dragon Ancestry). Is there a certain dragon can I be a child so my Eldritch blast will be more effective?

Heyo! I heard DnD.
I don't think so. Dragon Ancestry boots spells of the same element as your bloodline.
Eldritch Blast does Force damage, not elemental.

Sigh.
Are there at least any good Sorcery cantrips I should look out for?

Well, if you're in a more roleplay situation, go for Prestidigitation. Always.

Message is a pretty neat one for espionage.

If you want a cool first level sorcerer-only spell, try Chaos Bolt from Xanathar's Guide to Everything. 2d8+1d6 damage, the damage type being decided by one of the d8s. If both d8s are the same, the spell bounces to a new target.

Yo those sound sick.