Please help: very picky eater!

I think I made a mistake! I wanted to determine which (canned) foods my
cat likes, so bought a large variety from Science Diet, Fancy Feast,
Pro Plan, Iams, Nutro, etc., mostly "premium" ones but also a few from
Friskies and Whiskas just to try them too. I kept detailed notes on how
she reacted to each can. The idea was that I would identify a small
number of her most favorites and from then on buy only those.

In a way, the experiment worked. I learned that she liked quite a few
flavors of FF, ProPlan, Iams; some of SD; almost all of the cheap ones;
almot none of Nutro Max Cat Gourmet; nothing with sardines in it. She
generally liked chicken and seafood, was less warm towards beef, etc.

The problem is that her behavior has become more finicky and
unpredictable. My details notes are useless because flavors she liked a
lot a few weeks ago, she doesn't want to touch today. She seems much
less excited by most foods than she did in the beginning.

I do realize that I may have helped cause her finickiness, and would
appreciate advice on how to get out of this situation.

She has no health or digestive problems, just this pickiness and also
what she liked one day she may not the next.