Reddit mentions of Sepher Ha-Razim: The Book of Mysteries (Sssa Special Publication) (English and Hebrew Edition)

Raziel is probably most famous for the book he gave to Adam. There are many versions of the story, including one where angels steal the book back from Adam out of jealousy. It supposedly passed through the hands of Enoch, Noah, and Solomon, inspiring the Book of Enoch, teaching Noah how to build the Ark, and granting Solomon great knowledge and power in magic respectively. Source

The origin of this story is pretty interesting: "The myth of the Book of Raziel grows out of a midrash attempting to explain the verse, This is the book of the generations of Adam (Gen. 5:1)." Source, also a good read

Raziel is mentioned in Targum Ecclesiastes 10:20 - "Do not speak evil of the king in thy conscience, nor in the secret of thy heart, nor in the most hidden place in thy house, curse not a wise man; for Raziel calls daily from heaven upon Mount Horeb, and his voice goes through the whole world; and Elijah, the great priest, goes, flying through the air like a winged eagle, and publishes the words which are spoken in secret by all the inhabitants of the earth." The Targumim are pretty old - they date back to the 1st to 7th centuries. This page offers an interesting theory about Raziel's early role in Jewish mysticism - not as the keeper of secrets but rather the revealer.

According to Maimonides (1135-1204) in his Mishneh Torah, Raziel is the chief of the order of Erelim, also the herald of God and preceptor of Adam.

Now, there is a 13th century medieval grimoire known as "Sefer Raziel HaMalakh". The true author is unknown, but it's commonly attributed to Eleazer of Worms or Isaac the Blind, medieval writers of the time. It draws heavily on Sefer Yetzirah and Sefer Ha-Razim, the former being the oldest and probably the most important Qabalistic text.

As for the Sefer Raziel itself, you can read it online here. Steve Savedow's translation is unfortunately not great, the amazon reviews sort of speak for themselves, but it's better than nothing. You may find something interesting there.

tl;dr Raziel is a very old and important angel, considering he derives from Genesis 5:1. If you are trying to connect to angels in a Qabalistic context, I'd highly recommend starting with the books they originated from, like Sefer Raziel and its predecessors. Hope this helps.

Well... You should totally read this book. It's available on that site for free. The book is a scholarly study of magical thinking among (primarily) a Jewish community in Europe. It's pretty fascinating. There's a whole chapter dedicated to name magic if that's what you're really looking for. Just glance through it, there's probably something in it for you. Honestly, this is the best book I have for you and what it presents is most similar to modern Judaism.

A great book on influential Jewish stories, myths, and legends is Tree of Souls. I'm honestly in love with this book. If you need to add some mythic Jewish characters or fables, this book has it. Many of the stories come from sources still used among Jews, so a lot of them have some relation (however marginal) to modern Judaism.

There's also a book called "Aramaic Bowl Spells: Jewish Babylonian Aramaic Bowls" by Shaul Shaked, James Ford, and Siam Bhayro which is has some pretty awesome curses and what not. You can access it here. Not sure how much use it'd be for you. Everything discussed in this book has little resemblance to anything in modern Judaism.

There's also book called Sepher Ha-Razim which was supposedly given to Noah by Raziel, an angel of secrets. Sepher Ha-Razim is... Well... Really weird. I think that's the best term to describe it. Like, we aren't talking about cute, little spells from Charmed or whatever; we're talking about killing lions, bathing in their blood, and hiding lion hearts in the middle of the city. You can buy it here, but it's probably not worth it unless your goal is to repeatedly say, "What in the world?" Sepher Ha-Razim (like the Aramaic bowl spells) has little resemblance to anything in modern Judaism.

You should also totally include golems. Maybe also Lilith and dybbuks. These concepts are discussed in the first book I've mentioned here.

Anyway, half of what I've presented here is outdated or heretical, and the other half is folklore. But it's all still probably fun to mess around with in a fantasy setting! Especially the first book.