You’ll need code2001 and Cambria Math to see this properly.

This should be ABCD in Mathematical Fraktur, with html codes: 𝕬𝕭𝕮𝕯

Same thing, with real characters: 𝕬𝕭𝕮𝕯

Here’s some Linear B: 𐀀 𐀁 𐀂 𐀃

With utf8 characters: 𐀀 𐀁 𐀂 𐀃