There used to be this exchange in 2017-2018 where we bought currencies that weren’t listed in any of the major exchanges. The UI was just a black screen with numbers...it didnt feel like other exchanges. It’s not cobinhood, Kucoin, Mercatos etc.
Gdax? That's coinbase pro now I think
Cryptopia?
Gemini?
Nope, not GDAX and Gemini.
I remember the way to transfer to it was a little different than the rest. They would give you numbers/codes to store and didn’t have a login as such.
Cryptowatch? That was all black but I don't think it had unlisted alts.