First, this ARTICLE might give some insight into asking a question, in a way that will attract attention.
Next, I assume that you mean PrE 3. Do you have the PrE 3.0.2 update? If not, it would be advisable to get it for other reasons.
Now, with regards to more Transitions, two sources would be Hollywood FX, and New Blue. Both have Transitions that should work in PrE, though with Hollywood FX, you might need to do a bit of modification. Then, ProDAD offers Adorage, which is a Transition application. Another is Pixelan's Spice Master. I have many of these, though I have to admit that I do not use them that much.
Are there any particular Transitions that you wish to use?
If you're merely asking if you can add more transitions to the program, the answer is yes, there are a number of plug-ins (most designed for Premiere Pro) that can also be added to Premiere Elements.
Here is one source:
I had never seen that site, though maybe because I use a Butt Cut, Cross-Dissolve, or a Dip-to-Black for 99% of my work. Still, I have some add-ins and a couple of plug-ins, that can create many, many more. Of these, I highly recommend Pixelan's SpiceMaster. I use those more as Effects, than Transitions.