Prototypes/One-offs

pro·to·type
ˈprōdəˌtīp/
noun
1.
a first, typical or preliminary model of something, especially a machine, from which other forms are developed or copied.

 

one-off
BRITISH  (informal)
adjective
adjective: one-off
  1. 1.
    done, made, or happening only once and not repeated.
    “one-off tax deductible donations to charity”
noun
noun: one-off; plural noun: one-offs
  1. 1.
    something done, made, or happening only once, not as part of a regular sequence.
    “the meeting is a one-off”
    • a person who is unusual or unique, especially in an admirable way.
      “he’s a one-off, no one else has his skills”