They launched a game store this year, and they sell pro accounts ("Nitro") with extras like animated avatars, higher streaming quality and free access to some games from the store.

They have a premium service, but I can't imagine they're making enough off of that. From what I can tell, they aren't making money, and are just spending investor capital

Game market, animated avatars, extra emojis, etc https://discordapp.com/nitro

Discord Nitro, their premium service, and they opened a game store this year.

It doesn't make them much but I believe they sell a premium version with access to stickers and other stuff for chatting, and they have a video game store for PC now.

It’s in the article... (and also what they’re expanding into)

I'm sure they don't. You can pay to use an animated gif as your avatar and some other useless gimmicks, and as you can imagine, the % of users who pay is abysmal.

Selling user data.

Do you have a citation for this?

Same way slack and moviepass do: Not really.

Unless you consider taking VC captial "making money"

The money my company pays Slack each year could buy a house in most US states.

Slack makes good money.

Slack has premium plans that they make money off of.