Now that we're getting into the business of tagging costumes/craft essences as chartags too via topic #19844, I really think this should be taken care of. As things currently are, a number of those newly created and upcoming costume tags will run into the same thing and worsen the already existing problem.
Jeanne d'Arc (Alter) (Festival Outfit)_(Fate), is pretty explicitly a costume of Jeanne d'Arc (Alter) (Fate). But the current tagging system means that in lieu of this, we're supposed to have this. This makes no sense. It's the same character. In different clothes. There is no logical reason that if I look up Jeanne Alter art, I shouldn't also get her Festive Outfit in the results. Or her swimsuit. Or her Shinjuku outfit. This is how it works for other Fate characters, and in other gachas. When you look up a character you get their variants and costumes.
It already isn't consistently applied either, just look at how many results jeanne_d'arc_(alter_swimsuit_berserker)_(fate) jeanne_d'arc_(alter)_(fate) gets where only swimsuit Jalter is present. Same with saber_alter santa_alter and saber_alter artoria_pendragon_(alter_swimsuit_rider)_(fate), even though the saber_alter wiki has a line saying not to tag it with those two forms.
That's pretty telling, people expect them to be tagged just like other characters but they aren't. They should really be brought to the same standard even if they have catchalls. Yeah, sure it'll tack on some extra chartags on certain pictures, but this is a problem caused by Fate doing the bullshit it does, and shouldn't get in the way of properly tagging things to improve searchability.
Right now you need a 4 tags search just for every form of Jalter.