The rocket motor browser provides a way to walk through the 771 rocket motors available. Start out by choosing one of the high-level ways to narrow down your search, and then more specific options will be available for refining your search down to a manageable size.
If none of these is quite right, try going to the advanced browser.
Start out by selecting a category of total impulse (size or power):
Start out by selecting a basic motor type:
Start out by selecting a single manufacturer: