I think most of the time in regards to effects?, I like to start with null (or zero). So I guess if my studio was called; Null Recordings and someone called to make a booking I would say; Null, sorry.
Besides; my studio is totally private; not for profit; not for commercial use. (hey Mr Taxman, are you reading this?)!!
OK, got my serious hat on;
Since my studio is totally private for my own needs I have no need to build-up a mega-list of presets but then again; almost all preset would probably need tweaking because each song is a totally new bag full of fun and surprises. I guess the term; always learning something new applies to 'everybody' no matter how much experience one has.
I will save effects presets that I tweaked but usually for things such as; Reverb because I might be wanting consistency across a particular style for an album I'm working on. Whereas for track EQ? those setting will definitely change. But often a track requires NO effects at all.
There are certain elements for an album that requires some consistency such as; reverb, I guess the same might apply for instruments such as; Kick and Snare, so that I can get a sense of consistency ((that sound)) that style for the album. Keep in mind though; often not all tracks require treatment at all if the source material is perfect for the song for example; a particular synth pad and such usually has a character and ambiance about it that stands on it's own and requires no further processing (effects)! Another good thing about; getting it right at the source.
In regards to virtual instruments; I start with presets and tweak them from there (more or less) for whatever works best for the song. But I have template projects on standby; readily available so that when nature (creativity) calls I'm ready to open the flood gates.