One that I was surprised not to see is Wirewood Channeler + Pemmin's Aura + 2 other elves =infinite of any color manamana
Others with elves
Voice of the woods + intruder alarm + five elves = infinite 7\7 elementals.
Going back to the channeler and Pemmin's Aura, you could add second Pemmin's Aura attached to any other elf with a tap ability to get infinite of that tap. Wellwisher for life, Immaculate magistrate for +1+1 counters, etc.
Others with elves
Voice of the woods + intruder alarm + five elves = infinite 7\7 elementals.
Going back to the channeler and Pemmin's Aura, you could add second Pemmin's Aura attached to any other elf with a tap ability to get infinite of that tap. Wellwisher for life, Immaculate magistrate for +1+1 counters, etc.