Balefire Dragon does not have an on-attack triggered ability, it has a combat damage trigger. This ability will trigger whenever Balefire deals combat damage to a player, regardless of other circumstances. So if Balefire goes unblocked, and actually deals combat damage to the opponent, then yes.
For actual on-attack triggers, such as Flameblast Dragon , no, they would not trigger.
August 17, 2019 10:38 p.m.
Thank you. I misread the card. So unfortunately cards like Combat Celebrant won't work either :(
August 17, 2019 10:48 p.m.
Correct. Anytime a creature is "put onto the battlefield attacking", it was never declared as an attacker, and thus never "attacked", even though it is "attacking".
It is still considered an attacking creature, so cards that specifically interact with attacking creatures, including the card itself, can still function. For instance, a Kor Scythemaster that is put onto the battlefield attacking would have first strike during that combat phase.