I take formes into consideration when there's precedence for it, e.g. the Rotom forms have each had a print with specific card names like Mow Rotom, Frost Rotom, etc.
Some Pokemon like the Shellos line have had uniquely named prints in the past -- but there's some gray area there, since the latest prints featured both formes in a single art. I think Unown is in this gray area as well. The recent Wormadam line is a bit of a gray area too because it received three different prints (Burmy didn't though), and yet they weren't named in a way to depict unique formes. (For cards that fall into this gray area I include general and forme-specific listings in my spreadsheet.)
Other Pokemon like Keldeo or Meloetta have never had specific forme prints, so there is no precedent to consider them neglected. (For Pokemon like this, on my spreadsheet I generally just include the number of arts for each forme in the Notes section instead, until such a time that they are separated by TPC.)
Yet another gray area is Meowstic, who doesn't really have different formes per se, yet its genders are functionally different. We'd almost need Meowstic F and Meowstic M cards.
So there's some room for a case-by-case basis, but in general I believe that using precedence as the factor is the most accurate.
I think it'd be one heck of a long list if we started taking typings into account.
There's also some difficulty here since the TCG doesn't have every typing, so the typings that
are there should take precedence (e.g. a water/ground Pokemon, since ground isn't depicted directly in the game, should probably be expected to be water, since it's more true to the Pokemon than fighting would be). Plus the Delta Species would make the list quite messy!