What kind of tapes and diskettes do you use?
Credit / debit cards, I wouldn’t worry about. Nor access cards.
How careful you have to be around magnets in general depends on the item. Specifically, the coercivity of its magnetic medium, how much magnetic flux / energy it takes to alter it. For card stripes, they are classified as HiCo (High-Coercivity) or LoCo (Low-Coercivity). Credit cards are all HiCo. Access control cards, employee ID cards, and gift cards are also commonly HiCo. There is more concern with LoCo. I’ve read that hotel room keys, visitor badges, and season passes are more commonly LoCo. Not sure where the coercivity of audio tapes or diskettes fall. Seems for audio tapes at least it can be different depending on the tape you have. Compact Cassette tape types and formulations - Wikipedia
Luckily, magnetic flux falls off rapidly with distance, it may not be an issue at all. Hopefully, Framework can give flux numbers at the surface of the keyboard / touchpad.
Also note that a lot of cards have moved away from magnetic stripes. If you are tapping your card or “dipping” your card into a reader rather than smoothly sliding the edge through, then it’s rfid, nfc, or direct contact chip. Those are all completely immune to magnets. Even access cards are often rfid these days.