Look in your PIP room, you have them pre-installed, balloons that is. You can also make them yourself in popular photo-editing software, such as A***e, which has "brushes" where you can pick about 2 dozen different ones. Those can be saved as a PD-friendly image, such as .png with a transparent background, and brought in to use.
Also, I'm sure DirectorZone would have many.
http://directorzone.cyberlink.com/pdr/#ob:1
HP Envy Phoenix/4thGen i7-4770(4@3.4GHz~turbo>3.9)
Nvidia GTX 960(4GB)/16GB DDR3/
Canon Vixia HV30/HF-M40/HF-M41/HF-G20/Olympus E-PL5.
Tape capture using 6 VCR, TBC-1000, Elite BVP4+, Sony D8 camcorder with TBC.
https://www.facebook.com/BarryAFTT