Why do people want nymphs so badly?
They aren't really that useful. Gravity nymph is... maybe.
Nymphs are useful additions to FG grinders and good for bragging rights if you have multiple of a same nymph.
Now hold on here, let's look at the nymphs:
Aether nymph: Costs a ridiculous amount to allow you to play a creature that's highly susceptible to CC giving you quintessence on a stick. It is rare to get mono aether to have so many creatures it /needs/ quintessence on a stick, and even rarer for aether nymph to fit in a duo. Only possible use: TU+Spider deck. Maybe. 2/10
Air nymph: Costs a ridiculous amount to allow you to spawn my UG. Pretty useful. But, the nymph dies quickly after using the gasses, and is also susceptible to PC. The only way to keep it alive is to make it a trio deck. Might be descent in a UG deck with no other source of damage besides UG spam, but if you're running that deck without other damage, you're doing it wrong. 5/10
Darkness nymph: Costs a ridiculous amount to allow you to liquid shadow everything. Can be used on your own creatures or as CC of lobo. But if you want it for the CC, use parasites instead, and if you want it for the vampire, use the card version of liquid shadow. 7/10
Death nymph: Costs a ridiculous amount of money to allow you to malignant cell stuff. Only has two real uses. Malignant celling your own field, and doing it to your opponents. Once it's ability is used twice, it's job is done. Until then, death has way cheaper ways of doing the exact same thing. 2/10
Earth nymph: Costs a ridiculous amount of money to get a card that's twice as good as arctic squid. Unfortunately, if you /need/ that much stall power, then you don't have time to wait until you can afford an earth nymph. Arctic squid is a better pick the vast majority of the time. Or for that matter, why not kill your opponents creatures instead of stalling out until the inevitable. 4/10
Entropy nypmh: Costs a ridiculous amount of money to get antimatter on a stick. And the ability costs less than antimatter. It, in effect, turns your opponents creatures against them, single handedly winning the game. Unless they possess the capacity to do
1 damage to it! In which case the nymph is screwed. 7/10
Fire nymph: Costs a ridiculous amount of money to get rage potion on a stick. This is great for CC, and when combined with heal, /and/ the nymph can survive one turn of play on the field. Unfortunately, fire is so good at rushing, there are a thousand better cards you could have played. It's nice in a firestall deck. 7/10
Gravity nymph: Worth having. Completely locks down your opponents deck and guarantees a win. If they're rainbow. 5/10
Life nymph: Not bad. It gives you adrenaline on a stick, and stacks well with adrenaline, and it's pretty durable. With all the life creatures out there, there's plenty of fish in the sea, and it can be used defensively when combined with thorn carapace and heals. But... by the time you have so many creatures you need the nymph, you've won the game. In most cases, adrenaline is a better card to have. Of course, I love it in my life-ramp. 6/10
Light nymph: After one use it becomes useless. The 10 HP helps, and it pays for itself. It's a decent heal-bot. 7/10
Time nymph: If time can afford the nymph, than it absolutely needs to draw. By using hourglasses. 3/10
Water nymph: Why the hell didn't you just take nymph's tears? Nymphomania sucks. 1/10
Noticing a trend here? Absolutely none of these cards makes or breaks your deck. All of these can be supplemented by spell cards which do the same thing for cheaper in the long run. Maybe nymphs give you a card advantage, but they cost you speed and quanta and don't always work well in a deck. Let's be honest here, let's say you could have one free nymph. Which one would you take? What would you use it for?
Would you take life nymph and use it to give adrenaline to creatures in the non-existant late game (if you haven't won by the time she's useful, you've probably lost)
Would you take gravity nymph and fight the oh-so-common rainbow (I'll give you a hint, the odds of you drawing it and your opponent being rainbow are pathetic)
Would you take air nymph and hit your opponent for 40 direct damage before wishing it weren't dead?
Would you take entropy nymph and pray they don't have any CC in their deck at all?
Or would you take fire nymph and love it in all 1 deck it's good in. (firestall. Any other deck it's in is pretty much a variation on a firestall. This includes the steam deck, which is either a stall, or better off without it.)
Or perhaps you should realize that just because you don't have something doesn't mean you want it.
They aren't as good as you think they are.