PF fireball "magic trick" feat is great

 

https://www.aonprd.com/FeatDisplay.aspx?ItemName=Magic%20Trick

https://www.reddit.com/r/Pathfinder_RPG/comments/ouuf6e/is_crossblooded_ever_worth_it_for_single_class/

https://docs.google.com/spreadsheets/d/1JcQLSzb84B0B_I0jKV87zWcHpcW8lREam8gJup1xaEY/edit?gid=146374033#gid=146374033

(he had it in there... the Cluster Bomb Magic Trick will do 20d6, without any funny business)

Fireball

Source Chronicle of Legends pg. 16
Vincent the Pyroclastic is a destructive force in the Society. He has caused permanent damage to and condemnation of more buildings in the Inner Sea region than any other agent. For him, incineration became an art. In addition to the feat, skill, or other requirements listed in parentheses for each of these tricks, you must have the Magic Trick (fireball) feat to use the trick.

Alchemist’s Inferno (Craft [alchemy] 9 ranks, Spellcraft 9 ranks): Using alchemist’s fire as a material component, your fireball sets everything it touches ablaze. The initial blast deals half as much damage, but targets that fail their Reflex saves also catch fire. A creature that catches fire in this way must attempt a Reflex save against the DC of the fireball spell to stop burning instead of the typical DC. Unattended objects automatically catch fire, though nonflammable objects burn for only 1 additional round.
Cluster Bomb (Spellcraft 6 ranks): You are able to throw multiple small explosions with a single spell instead of the normal effect. For every 2 caster levels, you toss a miniature fireball with a 10-foot radius that deals 2d6 points of fire damage. The grid intersection of all blasts must be within 30 feet of each other. If a creature is in the area of multiple blasts, it attempts a single Reflex save against the combined damage.
Concentrated Fire (Selective Spell or Widen Spell, Spellcraft 6 ranks): You can reduce the radius of your fireball by increments of 5 feet, to a minimum of a 5-foot radius. For each 5-foot increment you reduce the spell, you increase the spell’s damage by 1d6. This additional damage can exceed the spell’s maximum damage.
Sculpt Flames (Reach Spell, Selective Spell): You can alter the shape of your fireball to send its fire along the path you desire. When casting the spell, you can change the area to one 5-foot square per caster level. The spell’s area must be continuous and unbroken when cast. If its blocked or otherwise interrupted by a 5-foot wide or larger environmental feature like a wall, the spell fails. A creature only takes damage once from a fireball cast in this way, even if the spell’s area intersects with the creature multiple times.
Where There’s Smoke (Craft [alchemy] 6 ranks, Spellcraft 6 ranks): Using a smokestick as a material component, you make your fireball leave behind a thick cloud of smoke in the spell’s area for 1 minute. A moderate or stronger wind dissipates the smoke in 1 round as a smokestick. When using a smokestick in this way, your fireball deals only 1d6 points of damage per 2 caster levels (maximum 5d6).