What ways can a character (PC or Monster) prevent an enemy from casting counterspell?
What I can think of so far:
- Surprise the enemy and win initiative
- Cause the enemy to be incapacitated (or stunned/paralyzed/unconscious)
- Provoke the enemy into using a reaction earlier in the round (readied action, opportunity attack, previous spell)
- Avoid using perceivable spell components
- Sorcerer subtle spell metamagic
- Level 20 Druid Archdruid feature
- Casting a spell with only material components (eg. Minor Illusion)
- Prevent somatic components
- The enemy is holding objects in both hands
- Block line of sight (often interferes with targeting)
- Spells such as Fog Cloud, Darkness, etc.
- Physical barriers such as walls or large creatures
Are there any other options available that I am missing?