Tier Discussion, Class Balance Discussion or anything similar will NOT be tolerated in this thread.
The main idea behind this thread is to give creative ways to make encounters difficult for our spellcasting players, without making them feel as if they are completely useless. A lot of these ideas I've seen used in pre-generated adventures, especially Worlds Largest Dungeon.
#1 - Use of Silenced areas in a dungeon. This does not indicate traps. I'm talking about areas of the dungeon where noise does not do anything. Silence (as the spell) only gives a save if it is cast on a person. The effect (if triggered by a trap, or if it's just an ongoing effect suppresses all noise with no save.
#2 - Force concentration checks as a result of spooky dungeon features. Perhaps there is a constant cold draft that keeps the characters from being comfortable and staying warm. Perhaps it imposes a penalty on all concentration checks and forces concentration checks whenever a spell is cast. Maybe there are odd sounds in the dungeon?
#3 Use intelligent guards, perhaps there is a BBEG and he obtained a lock of hair. Now he can scry on the group, or send enemies at them.
#4 Wild Magic zones/Planar travels. - Use of planar magic can get very fun. Perhaps spells of a certain type dont function at all (common in planar settings). Or perhaps whenever a spell is cast it has a chance to produce a random effect that is uncontrollable by the player. These can get very fun, maybe the mage tried to haste his allies but instead he polymorphed them?
#5 Use grapplers - sure the arcanists might be able to dimension swap/dimension door away but at least you can try and pin them in a hold. Particularly useful in ambushes/outdoor encounters especially at lower levels. (Crocodiles!)
Anyone have any other ideas for making encounters that specifically challenge the casters or party more as a whole than simply throwing monsters at the group?