Custom Trick Arrow List

Acid arrow

Regular attack roll
4d6 acid damage and –2 AC + 2d6 next turn

Smoke bomb arrow

30ft diameter sphere obscured

Firework arrow

Regular attack roll
2d6 force damage + blinded (DC15 con save)

Exploding arrow

Regular attack roll
4d10 force damage

Shrapnel (Cone) Arrow

All creatures in the cone make a DC15 Dex save, half damage on a success
3d8 + Dex damage to enemies in a 30ft cone

Penetrating Arrow

Regular attack roll (all enemies in a line as far as the bows range hit)
+3 damage, 2 less damage to each enemy it hits behind

Knockback (bola) arrow

Regular attack roll
Regular bow damage + 10ft knockback (prone on a crit)

Sticky arrow

Str check dc 15 + difficult terrain

Item type

Ammunition

What about magic bow damage?

If you need to make an attack roll with the arrow, then you add the magical 'to hit' bonus as normal.
If the damage adds your dexterity, or uses the regular bow damage, then you add any addtional magical damage from the bow. Arrows like the explosive or acid arrows have their damage come from other sources (explosions or the acid itself) rather than the piercing of the arrow, hence the ommision of magic damage from those arrows.