I'm assuming you mean effects that use gimmicks. I personally think the best gimmicks are the ones where the performance is truly great or significantly enhanced. I understand you aren't too interested in card magic, and that's fine, so I'm gonna give you some great effect you might really like.
1st off, check out
Angle Z by Daniel Madison. Not exactly a gimmick or a gaff, but some might qualify it as one. It is one of the easiest yet one of the most powerful card effects out there. Buy the full DVD, you will learn amazing principals you can apply to it (including an impromptu signed card version). (DVD is $15, Download is the same thing but $25 since they are trying to clear out the DVD's from the wearhouse) . (Someone told me it comes free with Madison's cards. I don't know if that's true, but if it is, you should go with that. Also, if it is true, than dang it...).
The Raven, is a very powerful coin effect.
For Mentalism, you may want to check out The Amaze Box (
The Black Version is better but $65, the
White one is smaller but only $45)
You may also like
Dress Code by Calen Morelli
.
Since you said you want to focus on Mentalism, here are 2 brand new releases everyone is Raving about.
Akkelian Envelopes by Spidey
are a great utility that allow you to work wonders.
Cipher is E's new Mentalism app that allows you to retrieve specific info without your audience realizing.
These are just a few of the critically acclaimed effects out there on the market to get you started. The best effects are the ones you love and will actually perform - and the only ones you should get.
one more thing - buying these effects is useless if you don't work on your performance. If you make the performance about the tricks, it sucks. Work on your performance to give a great experience to your spectators.