When Astral Dragon enters the battlefield, it triggers, creating six token copies of Mechtitan Core that are 3/3 Dragons in addition to their other types.
Activate Ashnod's Altar twice by sacrificing two of the Mechtitan Core tokens, adding ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) .
Activate a Mechtitan Core by paying ({5} magic symbol) and exiling it, three other Mechtitan Core tokens, and Astral Dragon, creating three 10/10 Mechtitan legendary creature tokens.
Put all but one of the Mechtitan tokens in your graveyard due to the legend rule.
Mechtitan Core triggers twice, returning all cards exiled to create the Mechtitan tokens from exile to the battlefield.
When Astral Dragon enters the battlefield, it triggers.
Resolve the Astral Dragon trigger, creating six token copies of Mechtitan Core that are 3/3 Dragons in addition to their other types.
Repeat from step 3.
Once you have infinite ({C} magic symbol) , you may forego sacrificing Mechtitan Core tokens to Ashnod's Altar, and then target any other applicable permanents using Astral Dragon.
Results
Infinite colorless mana.
Infinite creature copies of noncreature permanents.