Welcome to Librarium Online!
The standard are AOEs, and just let them deviate, spells can be boosted if needed.
Probably one of the most amusing things I've ever done was against my cryx buddy and his damn bane thralls. I had wasted a turn of shooting by declaring shots against them the turn before 9without realizing they had stealth), so this turn I smiled as he was roughly 12" away still (he was headed sideways towards my other goodies). I activated my trenchers, he grinned, as he thought I would whiff again, and I announced a bayonet charge against his banes. 9 inch move put me well within the needed 5" and I promptly splattered the battlefield with bane bits. He just shook his head as he hadn't thought I could stop his banes before he got to my jacks that were reaking havoc on the other side of the board.
Another alternative to it is running a low def model up into or next to them and then hit it's back arc with your spells or AOEs. Many a time have my lancers strutted up and been chain lightning in the back, taking no damage (but being hit on a 4+), and causing 5 banes to be auto hit and shredded
16,000+ of Eldar (only need flyers)
7,000+ of Nids (want heirophant)
6,000+ of Space Marines (need rever titan)
4,400+ of Cygnar (all models for the faction)
1,500+ of Legion (just started)