Neyali, Suns' Vanguard

The second ability of Neyali, Suns' Vanguard triggers for each player you are attacking with one or more tokens. It does not trigger if you are attacking a planeswalker a player controls, but not that player.

The effect allowing you to cast the exiled card if you attacked with a token continues to apply even if Neyali leaves the battlefield or another player gains control of it. It also continues to apply during later turns—as long as you attacked with a token during those later turns.