Commander Classes

Gathering Commanders
Tip: Make all gathering commanders level 37 and assign points according to the screenshot below.
 * Cleopatra VII
 * Joan of Arc
 * Gaius Marius
 * Sarka
 * Constance
 * Centurion

PvE Commanders
Tip: PvE Commanders, talented on Peacekeeping using less AP (action points) and dealing a higher damage to neutral units
 * Lohar
 * Aethelflaed
 * Boudica

Infantry
 * Richard I
 * Charles Martel
 * Constatine I
 * Alexander the Great
 * Sun Tzu
 * Eulji Mundeok

Calvary

 * Minamoto
 * Genghis Khan
 * Coa Coa
 * Saladin
 * Pelagius
 * Baibars
 * Belisarius

Archer

 * Yi Seong-Gye
 * El Cid
 * Hermann
 * Kusunoki Masashige

All In One
These builds are perfect for mixing troops.
 * Scipio Africanus
 * Julius Caesar
 * Frederick I
 * Hannibal Barca

Conquering

 * Hannibal Barca
 * Julius Caesar
 * Fredrick I
 * Mehmed II
 * Charlemagne
 * Scipio Africanus
 * Osman I
 * Baibars (Recommended for calvary)

Flag / City Defense
Any commander with a garrison talent tree can be used for city or flag defense. When assigning a commander with garrison talent points make sure they wont be needed as a primary commander for open field battles but using the commander as a secondary commander works fine as only the primary commander talent trees are taken into account.
 * Richard I
 * Charles Martel
 * Constatine I
 * Yi Seong-Gye
 * Eulji Mundeok
 * Sun Tzu
 * Kusunoki Masashige
 * Hermann
 * Pelagius

Multi Purpose
These are commanders that are not recommended for battle due to their weak skills but can be used to do perform different types of tasks depending on the assigned talent tree.
 * Markswoman (Peacekeeping/Archer/Skill) - Recommended for barbarian hunting
 * City Keaper (Versatility/Infantry) - Recommended for gathering using the versatility tree
 * Dragon Lancer (Calvary/Versatility/Mobility) - Recommended for gathering using the versatility tree
 * Lancelot (Calvary/Versatility/Mobility) - Recommended for his speed (capture runes or kill gatherers)
 * Tomoe Gozen (Archer/Versatility/Attack) - Versatility tree can be used to reduce AP for Barbarian hunting and also gathering. She can also be used as an archer commander but isn't recommended.