Locked engage around cage
This type of composition works very well with Veigar because it turns Event Horizon into an almost forced trap. Jarvan IV or Leona can create the first point of contact, giving Veigar a target whose path is already limited. Instead of having to guess where the enemy will dash or Flash, he can place cage around a fight zone that has already been imposed. This makes his W more reliable and his ultimate much easier to convert on an isolated or low-HP target.
How to play it. The ally must engage within follow-up range, not too far ahead of Veigar. The right timing is engage first, cage second to close the exit, then burst the target that can no longer reposition.
Disruptive frontline in zone
Veigar likes allies who disrupt enemy entry without completely scattering the fight. Wukong and Thresh can create space, disturb access to the backline, and give Veigar a few decisive seconds to choose a useful cage. This is not only about protection: their presence forces enemies to slow down or path around, making movement easier for Veigar to read. The more the enemy frontline hesitates, the more dangerous cage becomes.
How to play it. Play around the same zone. If the frontline forces enemies to back away or path around, Veigar should place Event Horizon on the likely exit, not necessarily on the first visible target.
Peel and defensive reset
This type of composition gives Veigar what he does not naturally have: a second layer of safety when assassins or divers cross his first zone. Janna and Thresh can slow entry, interrupt a commit, or offer an exit after a defensive cage. This changes the fight a lot, because Veigar no longer has to spend Event Horizon at the first sign of threat. He can wait for the real engage, save burst for the target that commits, then punish the enemy who spent their entry tools.
How to play it. Veigar should stay near the peel zone instead of looking for an overly forward cage. The goal is to let the enemy enter just enough to be punished, not enough to kill the AP carry.