XCOM 2 Tutorial: Using the Starting Soldiers mod.
The Classes in XCOM: Enemy Within & XCOM 2: WOTC, Ranked
XCOM Hero, XCOM Wiki
Learning from XCOM, 3: classes, advancement, and special moves
XCOM 2: War of the Chosen review—A world worth saving
Xcom TheGamer
Steam Workshop::[WOTC] Hero Classes Rebalance
XCOM 2: Best Classes, Ranked
Othercide - Missions Guide
XCOM 2: The Best Base Layout
Mod categories at XCOM2 Nexus - Mods and Community