hi am a blood hunter player who is wanting to get a 1 level dip for magic, 3 or more cantrips for a single level dip and some intresting features, any tips? (btw the way im using int for spell casting, about +3)

So I know this answer isn't quite conforming to the question, but why don't you just pick the Order of the Profane Soul? You get warlock-style spellcasting with your Hemocraft modifier, and you get to keep all the (quite good) Blood Hunter features at the same pace. Honestly, multiclassing just feels like a waste in this scenario. I'd definitely go Profane Soul if you want a BH + Magic.

But, if you are dead set on taking a MC dip, the first question is what classes do you have the stats for? To MC into Druid or Cleric, you need at least 13 WIS, and for Sorcerer and Warlock, at least CHA 13. Since you already have a +3 INT, I'd say either Wizard or Artificer. Probably Artificer, as a Wizard's d6 hit die is gonna reduce your max HP a lot, which is bad for BH. But you may need more than a 1 level dip to get magic from Artificer (someone please correct me if I'm wrong, which I probably am).

And keep in mind you either need STR 13 or DEX 13 to multiclass *out* of BH. So if you don't have those stats, you literally can't MC.

But keep in mind that a 1-2 level dip is only going to get you at most 3 1st level spells. Honestly, not worth it for the slowdown of BH progression. You can do insane amounts of damage just with mundane weapons and your Crimson Rite. Keeping all your levels in BH lets you make that Hemocraft die go up faster.

If you're Int-Based, and you want to get at least 3 cantrips, literally the only choice is Wizard. Wizard and Artificer are the only Int-based Spellcasters, and Artificers only get 2 cantrips while Wizards get 3.

A single-level dip of Wizard is decent... you can learn 6 spells right up front, and you also get a spellbook that you can add more first level spells to without needing to actually gain any more levels in Wizard... you just need to find scrolls and, potentially, other spellbooks. You only get two spell slots, but you can Ritual Cast any spells in your spellbook without even needing to prepare them. 

However, the other nice thing about Wizard is the fact that they get their subclasses at level 2 instead of 3, so you only need to dip 2 levels to at least get those features. Bladesinger is a great choice... the Bladesong feature keys off of your INT score and you get a number of uses dependent on your Proficiency Bonus and not your Wizard level, so the feature will continue to improve for you even if you're still mostly a Bloodhunter. However, the boost to concentrating on spells might not come up as often, since there aren't as many super-impactful first level concentration spells.

Another good option is War... it's best feature is a sort of "mini shield" that can give you a +2 to your AC (or a +4 to a saving throw) as a Reaction. The downside is, after using that feature, you can't cast any leveled spells on your next turn... which is a big problem for a single-class Wizard, but for someone just dipping into the class, you're probably planning to just Attack or cast a cantrip on your next turn anyway, so it won't be nearly as big of a problem for you.

Appreciate the help, thanks