Is Lamport's One Time Signature used as a primitive to construct any other cryptographic protocols?
I don't know of a use of Lamport's scheme precisely as Lamport originally published it; however if we include generalizations of the idea (such as Winternitz signatures), then it has been used as the basis of Hash Based Signatures, such as this proposal
- Lamport itself isn't fundamental; it's just the prototypical example of a one-way signature.
- A one-way signature isn't a "primitive" any more than an RSA signature is; it might be more accurate to describe it as a "building block".
However, yes, one-time signatures are a keystone operation in Lu, Au, and Zhang's 2019 Linkable Ring Signature scheme.
(Ring Signatures allow users to sign a message as an anonymous member of a set of users; Linkable Ring Signatures allow multiple such signatures by the same anonymous signer to be shown to be such.)