Q: What can we do about certain card types becoming overworn (Goals in Aquarius, Choice cards in Choose One)?

A: We suggest that you use card sleeves to protect these overused card types. If you’re unfamiliar with these, they are simply custom-sized plastic pockets to put your card in to protect them from wear. People who play games with collectible cards often do this to protect cards they want game with but don’t want to damage for their collectible aspect. Or avid gamers do it for the reasons mentioned here: to protect frequently used game components. You should be able to still shuffle a deck with all cards in sleeves, though it may take some getting used to.

If your cards are already over-worn such that it’s interfering with the secrecy required for game-play, look for card sleeves with opaque backs, or try sliding an extra card of a similar or slightly larger size behind the card in question, so that you only see the extra cardback (regular playing cards would work fine for this, for example, as long as they are close to the same size so that they can fit in the card sleeves you’ve acquired.)

You can find card sleeves for almost any size cards, so search online and see what’s available. You’ll need to know the size of the cards, which you can get by simply taking a ruler to them. For a more comprehensive list, however here is one that someone has compiled as a reference on the tabletop gaming reference site BoardGameGeek.com

This informational website is incredibly dense, so it starts with a lengthy description of how to read the chart. Then scroll down for a list of games by title. There are pages and pages of them, but you can click to the alphabetic range you need:
https://boardgamegeek.com/geeklist/164572/card-sleeve-sizes-games?titlesonly=1

Find the game you’re interested in on the list and click the NUMBER to the left (clicking the name gets you to an interesting game description page, but not the card sleeve sizing recommendations). Aquarius is on there, as is Fluxx, but Choose One was not deemed popular enough to include specifically, though the cards should be the same size as Fluxx, which IS certainly on the list.

Although they show two separate lists for first and second edition of Aquarius, to our knowledge, they are exactly the same size. That said, the second edition is more common these days. The Goals have round images, and the deck includes diagonally split cards.