So I was wondering what spells a bloodhunter might be able to cast if any. I can't seem to find any help or details on what spells Bloodhunters can use, so if someone could kindly help me, that would be much appreciated.
The Blood Hunter class is fully detailed on the DnDBeyond site. It gains a number of features such as 'rites' (taking damage to enhance your weapons), curses etc, but does not cast spells by default.
Only the sub-class Order of the Profane Soul casts spells once you reach 3rd level. Their spellcasting feature works in a similar way as a warlock. A table is provided that indicates the spells they know and the spell slots that they get.
Standard Blood Hunter cannot cast spells
The Blood Hunter class by Matt Mercer is not a spellcasting class, it does not have the spellcasting feature and gains no spells and therefore does not have a list of spell it can cast. Instead they get a number of features that in previous edition would have been called "spell-like" or "supernatural" abilities (these terms do not exist in 5th Edition).
The class has two main spell-like are its Crimson Rite and Blood Maledict features. Crimson Rite grants a number of different rites to add magical damage to your weapons, each rite dealing a different damage type. Blood Maledict allows you to choose a number of features which are very similar to spells in the form of Blood Curses. Each Blood Curse is unique and works as per the rules given in the class description. They do not count as spells however.
Order of the Profane Soul
There is one subclass of Blood Hunter called the Order of the Profane Soul that does get a form of spellcasting. This subclass grants the Pact Magic feature similar to the warlock. Profane Soul Blood Hunters are to warlock what the Arcane Trickster Rogue and Eldritch Knight Fighter are to wizards. They are half-casters that use magic in the same manor as the main spellcasting class but to a lesser extent.
This subclass gains fewer spells as a lower rate than a true warlock. They start with 2 cantrips, and 2 spells known when they choose the subclass at third level. Scaling to 3 cantrips and 11 spells known at 20th level. Each of these spell are chosen from the warlock spell list, not including the expanded spell list granted by each of the warlock patrons.
The Order of the Profane Soul do still choose a patron however. These patrons instead grant unique powers and once per long rest casts of certain spells at 7th and 15th level.
So the answer to your question is:
Blood Hunter's cannot cast spells, unless they take the Order of the Profane Soul subclass. Then they can cast spell from the warlock spell list to a limited degree.