Already known recipes, pets, mounts
 

There used to be a mod that turned known recipes blue, similar to the red "can't be used" coloring. Does that mod still exist/work? Is there a new one that supports mounts and pets as well?

I noticed AlreadyKnown and RecipeKnown haven't been updated in awhile. Do either of them still work at least for recipes?

I use AckisRecipeList.

GnomishVendorShrinker does this, along with making a lot more items fit on the vendor screen (turns each entry into a line, instead of a big rectangular box). It colors known recipes/pets/whatever blue.

I use TradeSkill Info to colourise known/unknown recipes as well as it's very useful tooltip information.

For minipets, try Collectinator or Pet Shop. Collectinator provides an expandable list and PetShop provides tooltip information.