Refugee ships of the future.
The first time that humanity made contact with alien life was in 2193 by the Verzian Federation. The Verzian Federation consisted of 4 races, the Gren (Reptilian), the Jender (Avian), the Fiontes (Primate) and the Kendase (Reptilian/Amphibian hydrid) - All of which are located in the Alpha Centauri cluster. Contact with the federation was peaceful since it was an expedition to explore unknown space.
After diplomats agreed to key terms, trade came soon after with both sides prospering shared resources, knowledge and culture.
We're not entirely convinced this happened. Rumor has it this is one of the many conspiracy theories running around OutSol