Another source in the last half a decade or so is digital coin "mints."

Quick look on coin market puts the total market value at ~$3 trillion. Yet that money effectively was created from nothing. It's basically money printing.

With credit cards that accept digital coins as financial sources it's also started to affect the actual markets significantly.

From the charts shown, markets have also gotten quite a bit frothier, with larger swings and spike / drops in margin, since 2020 when coin valuations really took off.

Personal view, it probably also contributes since it's less "real" from a certain perspective. Just digital numbers to wager, that don't really mean the same as mortgaging your house. "Eh, just wager like 10 or 20 digi-coins on margin." Except that's like $1-2 million these days.