The 5e rules for treasure hoards are found in the DMG. Page 133 to be exact.
But if you'd like to see an alternative....
A Gold Dragon you say?
Here, roll up treasure from
these charts.
This is what a Gold Dragons hoard looked like back in 1st ed.
They were listed in the Monster Manual as having Types H, R, S, & T
The treasure hoard charts went from A - Z, each entry telling you what the % chance was of it containing x type of loot (SP, GP, magic....) was.
For convenience I've translated the ranges it gave into the #/type of dice you'll need.
Type H
CP: 5d6 x1,000 - 25% chance
SP: d100 x1,000 - 40% chance
Electrum Pieces: 10d4 x1,000 - 40% chance (an ancient coin, no longer used. 2EP = 1GP)
GP: 10d6 x1,000 - 55% chance
PP: 5d10 x1,000 - 25% chance
Gems: d100 - 50% chance
Jewelry: 10d4 - 50% chance
Magic Items: Any 4 +1 potion, +1 scroll - 15% chance
Type R
GP: 2d4 x1,000 - 40% chance
PP: 10d6 x1,000 - 50% chance
Gems: 4d8 - 55% chance
Jewelry: 1d12 - 45% chance
Type S + T
Magic Items: 2d4 potions - 40% chance, 1d4 scrolls - 50% chance
This could well be a
fantastic hoard. The most loot the characters will ever see.... Or you could roll those %s & get NOTHING! (I've done that before)
Assuming you hit any of these %s, does this seem excessive? Eh. I mean, it's not like your novice PCs are
actually going to rob the LG guardian Gold Dragon. Right? So much of it can be mostly for show. And nothing says it must be easily portable (though that was the general idea back in 1st ed). So 40k GP for ex might take the form of several very difficult
(or even impossible - what if Davinci painted a ceiling mural for a dragon?? Stupid valuable, but.....) to transport & sell pieces of art/sculpture. But then I'll often throw something like this into my own modern games just to see what stories develop.
