Brudiclad, Telchor Engineer + Lightning Runner + Quasiduplicate

Brudiclad, Telchor Engineer

Lightning Runner

Quasiduplicate

How it works

1. Cast Quasiduplicate from your hand, targeting Lightning Runner and creating a token copy of them.
2. Move to combat, triggering Brudiclad to make a 2/1 Phyrexian Myr, then turn all tokens into Lightning Runner.
3. Attack with at least 4 Lightning Runners, creating 2 Energy for each Lightning Runner that attacked.
4. Pay 8 Energy into one of the Lightning Runners, creating an extra combat step and untapping all creatures you control.
5. repeat steps 3-5.