Polemos is a Daimon of war and battle. Excluding the universal offerings, some common offerings include:

Weapons

Blood or Depictions of It

Exercise Equipment

Boxing Gloves

Photos of Wars and Soldiers

Military Uniforms

War Medals

MREs

Paper Maps

Recruiting Pamphlets and Papers

For devotional acts, some activities that can be done for him include:

Learning About Wars in History

Learning About Battles in History

Boxing, Archery, and Other Fighting-Associated Sports

Researching War Heroes

Learning About How Animals are Used in Wars

Learning About War Ethics and Code