Other than the affixes Ruvanal mentioned, uniques and some sets are a wonderful way to get 'chance to cast xxx on striking or attack'.
Amulet
Atma's Scarab - amplify damage
1.08 Saracen's Chance - amplify damage
Gloves
Hellmouth - meteor, firestorm
Lava Gout - enchant
Laying of Hands - holy bolt
Helm
Ondal's Almighty - weaken
One-Handers
Coldkill - ice blast
Pompeii's Wrath - volcano
Guardian Naga - poison nova
Moonfall - meteor
Baezil Vortex - nova
Earthshaker - fissure
Schaeffer's Hammer - static field
Zakarum's Hand - blizzard
Fetid Sprinkler - confuse, attract
Hand of Blessed Light - fist of heavens
Plague Bearer - poison nova
Lightsabre - chain lightning on attack
Dangoon's Teaching - frost nova
1.08 Hexfire - hydra
Two-Handers
Stormrider - charged bolts, chain lightning
Hellslayer - fireball on attack
Cranium Basher - amplify damage
Blackleach Blade - weaken
Bing Sz Wang - frozen orb
The Vile Husk - amplify damage
Cloudcrack - fist of heavens
Todesfaelle Flamme - fireball on attack
Doombringer - weaken
Hwanin's Justice - ice blast
Ranged
Goldstrike Arch - fist of heavens
Skystrike - meteor
Witchwild String - amplify damage
Pus Spitter - lower resists
All are chance to cast on striking unless otherwise stated... off the top of my head, so may not be all that complete.
Mix and match... I had a lot of fun playing with a barb spamming frozen orb, poison nova, chain lightning, meteor, firestorm, weaken and blaze.
Amulet
Atma's Scarab - amplify damage
1.08 Saracen's Chance - amplify damage
Gloves
Hellmouth - meteor, firestorm
Lava Gout - enchant
Laying of Hands - holy bolt
Helm
Ondal's Almighty - weaken
One-Handers
Coldkill - ice blast
Pompeii's Wrath - volcano
Guardian Naga - poison nova
Moonfall - meteor
Baezil Vortex - nova
Earthshaker - fissure
Schaeffer's Hammer - static field
Zakarum's Hand - blizzard
Fetid Sprinkler - confuse, attract
Hand of Blessed Light - fist of heavens
Plague Bearer - poison nova
Lightsabre - chain lightning on attack
Dangoon's Teaching - frost nova
1.08 Hexfire - hydra
Two-Handers
Stormrider - charged bolts, chain lightning
Hellslayer - fireball on attack
Cranium Basher - amplify damage
Blackleach Blade - weaken
Bing Sz Wang - frozen orb
The Vile Husk - amplify damage
Cloudcrack - fist of heavens
Todesfaelle Flamme - fireball on attack
Doombringer - weaken
Hwanin's Justice - ice blast
Ranged
Goldstrike Arch - fist of heavens
Skystrike - meteor
Witchwild String - amplify damage
Pus Spitter - lower resists
All are chance to cast on striking unless otherwise stated... off the top of my head, so may not be all that complete.
Mix and match... I had a lot of fun playing with a barb spamming frozen orb, poison nova, chain lightning, meteor, firestorm, weaken and blaze.