Well, it's never a net gain - it's storing mana for next turn; inefficiently. I really don't see that being a problem if every colour has access to a bit of it.

The sell cost being fixed at does seem odd, mind you.

Temporal, delayed ramp is still ramp. It's like a "Rampant Growth Ritual" that can also be used immediately to fix your mana, but that scenario I find less likely. Celestial Prism can never give you a net gain of mana on its own.

EDIT: It actually seems I should be using the word 'Accel' here. For some reason I tend to mix up these mana slang terms. Regardless, has traditionally has no accel capabilities either.

It's not really ramp; it's colour fixing at 2-for-1. Heck; it's Celestial Prism, only you have to exile a dead thing instead of using a mono artifact.

So yeah; I can just about see every colour getting access to it. I agree that white should probably get the least of it though.

Of all the colors, I would think would be the one to get the least amount of gold token generation. The color has no affinity for ramp of any kind. Even blue has interest in artifacts so that's something to attach to.

Hexproof from black is now a thing. Though I would have gone for straight hexproof.

3W 2/3 Flying + Etb gives you a gold. Maybe 3W 2/2?

Four colour filter land cycle.

I find your storage land explanation pretty hard to follow. Here's how I see it:

Turn 1: Tap the storage land and another land to get a counter. mana effectively used. Turn 2: You can get the mana out of it, but then you aren't really getting anything out of it. Tap the lands again. Total of mana spent. Turn 3: You can finally tap the land to get +1 mana for this turn. That's 3 turns of building up and tapping lands five times. You can do it for longer for sure but then we're talking about a time frame of 3+ turns.

Compare to Vein of Gold: Turn 1: Tap this and two other lands. spent and you can get one mana of any color immediately. Turn 2: You have +1 mana of any color to use. That's one turn faster, fixes your mana, and uses "" less.

Also, you should think this in terms of cards like Nephalia Drownyard. You don't activate it when you can — you activate it if you really, really need to (you want to ramp into something or fix your mana), or maybe more commonly, when there's nothing else to do. And when there's nothing else to do, this is a pretty damn good thing to do.

Currently experiment antiblack with an immunity to having your creatures power and toughness be lowered (to protect again -?/-? effects that only black has access to, also stops power being lowered so feels more red as toughness alone would feel more blue-white-green that four coloured). I have no ideas if this works within the rules.

Maybe change it to "cannot be lowered by spells or abilities your opponents control" to avoid crashing the rules.

If it doesn't work just give hexproof variant that only protects from mono-black.

Understood.

I have changed it from "has fewer than that four colours" to "that isn't four or more colours".

Does this make the card more intuitive/elegant?