As far as I know, what
@Alphonse said is correct.
I will throw in a suggestion to look at plugins, particularly equalizers (EQ). EQs let you raise/lower the volume of ranges of frequencies in your sound. You can use it to make the voice's higher pitches quieter and its lower pitches louder, for example, making it seem deeper overall. It's not going to be the same as having an append--it will sound the same, just pitched differently, and appends are more than just pitch differences--but EQ can change the sound a lot.
Compression can also change the sound a good bit, making it sound more powerful and adding a kind of crispness to it.
I'm not an expert with these (someone who knows more might be able to do magic that I can't), but my experience, again, is that these won't magically create an entirely different voice, they'll just make the same voice sound (noticeably) different. But without appends, those and the Vocaloid parameters are basically what you have to work with.
Among the parameters, I'd recommend looking at BRI, GEN, CLE, DYN, and even Volume, as those can affect how cute/smooth/crisp the vocal sounds, too. We have a Tuning guide in the Resources section that has good information about parameter usage--check out some of the books.