Are EdDSA algorithms encoded by ASN.1 DER standards?
An EdDSA signature is a sequence of bytes encoded according to the EdDSA paper or its extension to more curves, or according to RFC 8032, which should be treated as opaque by callers.

In particular, for an instance of EdDSA on a curve $E$ over a field $\mathbb F_p$ of order $p &lt; 2^{b-1}$:


A public key is a $b$-bit bit string $n \mathbin\| \underline y$ encoding a point $(x, y) \in E$, where $n$ is 1 if $x$ is ‘negative’ and 0 if not, and $\underline y$ is the little-endian encoding of the least nonnegative integer residue of $y \in \mathbb F_p$.  Here ‘negative’ means $\underline x$ is lexicographically larger than $\underline{-x}$.
A signature is a $2b$-bit string $\underline R \mathbin\| \underline s$ encoding a point $R \in E$ like a public key, and a $b$-bit integer $s$ in little-endian encoding $\underline s$.


There is no ASN.1 formatting involved here.  Forget ASN.1, and forget ECDSA.  They are evil things.