Here’s a bit of mine.
1. Cutting tendons and turning your trget into a chicken, causing it to run uncontrollably in random direction, is often a one-shot kill, even for boss-tier enemies.
2. Have one of your party members dead. Be a buffed up necromancer with large health pool. Use Shackles of Pain on your target, then Living on edge on yourself. Next turn resurrect fallen comrade with Last Rites, dealing your full health worth of unblockable damage to self and enemy. You survive, they don’t.

3. Be a huntsman/pyro hybrid (Lone Wolf perk – even better). Step 1: Open a fight with a meteor shower from elevated position. There’s no Step 2.