A great assortment of shaders. If you are taking ideas for future packs, I would love to have one like RedactedSimple but where the color is behind the text instead of covering it up. Would be useful for a highlighter or whiteout/correction tape/fluid effect.
Viewing post in Make Visual Novels! RenPy Text Effects & Shader Pack! comments
Donezo. Redownload MVNTextShaderTags and MVNTSV1 for the new effects. You can customize them either by altering the tags or making your own via the instructions in MVNTextShaderTags or by altering the defaults in MVNTSV1 if you feel like braving the shader declarations.

This now includes the HighlightSimple and HighlightRecolor shaders. Highlight simple just applies the requested effect without altering the original text. HighlightRecolor gives you control over the original color as well to make it a single tag operation to use rather than needing to stack a dozen tags for legible highlighted text.
{hl}{/hl} does a simple highlight using a yellow highligher by default.
u__highlightcolor defines the color of the highlight if you make your own tag for it.
{hlrc}{/hlrc} does the same thing, but recolors the original text in the same tag.
u__highlightcolor and u__textcolor define the highlight and the text color respectively