Just some thoughts that come to mind looking over this...

textExplode, textConverge

backspace, type

disintegrate, build

blockFadeOut, blockFadeIn

They work beautifully so far, but I think we need to try to make this more like the other effects, and use "show" and "hide" modes of the same animation.  It seems other effects tend to use the "hiding" operation i.e. "explode, drop, fold, blind"

Also - a little curious about the naming of the effects:

$("div").show("text-explode") vs $("div").show("textExplode")

Should all the text effects be prefixed with "text"?

Anyone have any better names for these effects? 

A tidy branch that includes my current effects api changes and the text effects is here: https://github.com/gnarf37/jquery-ui/commits/effects-api-text

There is a "demos" page that shows the current text effects in that branch.