I'd have to agree with Katiana, briefpedia is great.
But I've also found it good to have a copy of Brief Encounters in your steno case or the back seat of the car as you head out to a last minute job - I've often had cause to flick through it as I sat waiting for a depo to begin, you'll always come up with one or two great briefs.
Have you tried Marc Greenberg's Steno Brief Machine? I write out a lot of stuff, but I did get some useful briefs from his site. I haven't used it in a while. You type in your English word and in seconds you receive a brief if it exists. However, I agree with Wendy W. Sometimes I find that I can stroke it as fast as trying to remember a bunch of briefs. Good luck.
It is important to know that the author of Brief Encounters was trained in StenEd.
All of her briefs and phrases are StenEd compatible.
What this means is that if you know one or more theories, or have adapted things in either on your own or by finding them online, the ones in this book (and the series of related works) may not fit with what you do.
But, it's interesting.
The other cautionary tale I have is a story of someone in school who tried to rapidly increase their speed by memorizing briefs and phrases. It did not translate into speed or accuracy. So, sitting down and practicing all the briefs presentes and memorizing them probably would not work.
I would say, select, modify if needed, see what sticks easily or expands without conflicting with what you have learned or do, and then do what you need to in order to own what you've chosen.