Biff Bam Boom from Comic Craft is a pretty solid option for most heavy impact sounds like "crash!" "pow!" "slam!" etc. It's also included in Abobe typekit, so if you have photoshop you can effectively get the license for free on this one. Badaboom from Blambot is similar and also included in Typekit.
Some "free for indies" fonts I love from Blambot include:
Crash Landing. Great for a powerful, chaotic impact like a "CRASH!" or for something like a "ZAP!" with a slightly cartoonish feel.
Blowhole. Ideal for "splash!" "Sploosh!" "squelch!" and other watery or wet sounds.
Blam blam. The name pretty much spells out what this one is for. Any sharp sound like "blam!" "shing!" "slice!" "crackle!"