A few of my favorites:

Nightshade, Small Antlers, and Deathbell

yields

Weakness to Poison, Lingering Health Damage, and Health Damage

Skeever Tail, Silverside Perch, and Deathbell

yields

Damage Stamina Regeneration, Ravage Health, and Health Damage

Snowberry, Hawk Beak, and anything that resists fire

yields

Resistance to all elements

What are yours?